CLEANING AGENTS  

Dust being composed of loose particles is removed comparatively easily by the use of various  pieces of equipment. Dirt however, owing to its adherence to surfaces by means of grease or  moisture requires use of cleaning agents as well as equipment if it is to be removed efficiently.  Knowledge of different types of cleaning agents is important so that deterioration of surfaces is  prevented. 

Water  

It is the simplest cleaning agents and some forms of dirt will be dissolved by it, but normally it is  used together with some other agent’s e.g. detergent water is not an effective cleanser. It doesn’t  wet surface satisfactorily as its surface tension prevent it from spreading. Hardness in water is  another consideration to be borne in mind.

Hardness in water 

It is caused by dissolved salts of calcium and magnesium usually bicarbonates and sulphates. Bicarbonates gives rise to temporarily hardness because they are removed by heating water above  72 degrees centigrade when scale or fur results. 

Permanent hardness is caused by the sulphates of calcium and magnesium which cannot be  removed by boiling but by water softening processes when temporary hardness is also removed. 

Hard water may be softened by: 

i. Addition of soda. Use of certain water softeners based on sodium sesqui-carbonate. ii. Laundry water softener- sequestering. Agents 3which form a complex salt with the calcium  and magnesium ions thus removing them from the water but forming no precipitate or  scale. These are usually expensive as relatively large quantities have to be used to  overcome the hardness. 

iii. Water softening unit e.g. permutit- the hard water passes through a container, filled with  resin beads containing ions more than sodium ions. This resin has a greater affinity for  calcium ions in the hard water than for sodium ions so an ion exchange takes place.  Calcium ions are removed from the water and are replaced by sodium ions which do not  cause hardness in water.

Effects of hardness in water  

▪ Have an adverse effect on the efficacy of some cleaning agents e.g. soap and soap –based  washing powders are wasted and form scum (lime scale) in the water. 

▪ It causes premature ageing o fabrics. The fibres degrade more quickly because of the  friction produced by the deposits from hard water  

White fabrics lose their whiteness and there can be over marking of coloureds. ▪ Cause scale and fur to be deposited in boilers, pipes and domestic appliances. 

Detergents 

These are cleaning agents which when used in conjunction with water, can loosen and remove dirt  and then hold it in suspension so that dirt is not re-deposited on the clean surface. i n order that  that they may do this detergents require three basic properties: 

a. Good wetting power to lower the surface tension of the water and enable the surface of the  article to be thoroughly wetted. 

b. Good emulsifying power to break up grease and enable the soiling to be loosened. c. Good suspending power to prevent re-deposition of soiling. 

There are many different detergents available in packets and bottles. Detergent may be soapy or  soap-less (synthetic). The basic ingredients of any detergent are surface active agents or  surfactants. These are primarily the wetting agents which lower surface tension of the water and  to varying degrees emulsify the grease and suspend the soiling. 

Detergents are also required to help loosen dirt particularly greasy dirt. The particles of grease and  dirt remain suspended in the detergent solution and do not resettle on the clean articles. 

Some of more frequently added substances are: 

• Alkaline builders- e.g. soda, borates to increase emulsifying powers. 

• Sodiun sulphate to enable the detergent to flow freely. 

• Foam and leather stabilizers to ensure lather is maintained and have some detergent

properties. 

• Flourescers are whitening or brightening agents. 

• Enzymes are complex proteins which break down organic substances e.g. blood, egg,  gravy, grass, milk, etc. 

• Germicides, perfumes and dyestuffs may be added. Perfumes are added to give a clean,  fresh fragrance. 

In order that the washing process should be carried out efficiently an ideal detergent should: 

1) Have good wetting powers so that the solution penetrates between the article and the  particles. 

2) Have good emulsifying powers so that grease and oil are broken up and to some extents  dissolved.

3) Have good suspending powers so that the dirt particles when removed are suspended in the  solution and are not re-deposited on the article. 

4) Be readily soluble in water. 

5) Be effective in all types of water and produce no scum. 

6) Be effective over a wide range of temperatures. 

7) Be harmless to the article and the skin. 

8) Cleanse reasonably quickly and with minimum agitation. 

9) Be easily rinsed away. 

10) Be bio-degradable. 

Types of Detergents  

i. Soap. It is cheap and effective in soft water  

▪ Forms scum in hard water 

▪ Difficult in rinse away  

▪ Is not effective in acid solution  

Soaps are used in hotels with name printed on the wrap. The tablets are issued for use in the guest’s  room. Private bathrooms and chalk rooms

properties. 

• Flourescers are whitening or brightening agents. 

• Enzymes are complex proteins which break down organic substances e.g. blood, egg,  gravy, grass, milk, etc. 

• Germicides, perfumes and dyestuffs may be added. Perfumes are added to give a clean,  fresh fragrance. 

In order that the washing process should be carried out efficiently an ideal detergent should: 

1) Have good wetting powers so that the solution penetrates between the article and the  particles. 

2) Have good emulsifying powers so that grease and oil are broken up and to some extents  dissolved.

3) Have good suspending powers so that the dirt particles when removed are suspended in the  solution and are not re-deposited on the article. 

4) Be readily soluble in water. 

5) Be effective in all types of water and produce no scum. 

6) Be effective over a wide range of temperatures. 

7) Be harmless to the article and the skin. 

8) Cleanse reasonably quickly and with minimum agitation. 

9) Be easily rinsed away. 

10) Be bio-degradable. 

Types of Detergents  

i. Soap. It is cheap and effective in soft water  

▪ Forms scum in hard water 

▪ Difficult in rinse away  

▪ Is not effective in acid solution  

Soaps are used in hotels with name printed on the wrap. The tablets are issued for use in the guest’s  room. Private bathrooms and chalk rooms.

Liquid toilet cleansers are based on dilute solution of hydrochloric acid. It should be used  with great care since high concentration may cause damage to surface of the pan, to  surrounding areas and to the person using it if the liquid is spilt. 

Window cleansers  

They consist of a water- miscible solvent to which small quantity of surfactant and possibly  an alkali are added to improve the polishing effects of the cleanser. Some also contain a  fine abrasive. The cleanser is applied with a cleaning rag and rubbed off with a clean, soft  cloth. Water or water to which some methylated spirit or vinegar can be used to do the job  quite well and cheaply but requires more rubbing. 

Soda And Ammonia  

These are alkalis and are used as grease emulsifiers and stain removal agents.

Strong alkaline cleaning agents based on caustic soda are used to unblock drains, cleaning  ovens and other large industrial equipment. Great care should be taken in their use as they  are strong materials. 

Acids  

Acids dissolve metals and are used to remove metal stains such as water stains in baths,  hard water deposits round taps and in WC pans, tarnish on silver, copper and brass articles.  Vinegar and lemon (cut or juice) are used for the removal of tarnish from copper and brass  and of mild water stains on baths. The acid produces further staining on the metals if it is  not washed off quickly and on sanitary fitments it may damage the glaze. More resistant  water stains may be removed with stronger acids such as oxalic acids. These should only  be used under strict supervision and in all cases of cleaning the acids must be thoroughly  rinsed away or they may harm the surface. 

Paraffin - efficient for the cleaning of baths but owing to its smell it is rarely used. Organic Solvents  

They are usually, methylated spirit, white spirit (turpentine substitute) and carbon  tetrachloride. They are grease solvents used for removal of grease and wax on different  surfaces. Methylated spirit and white spirits are highly inflammable while carbon tetra  chloride is highly poisonous if inhaled and should never be used in confined space. 

Bleaches And Disinfectants  

Bleaches are used for stained sinks, WC pans etc. They should never be mixed with other toilet  cleaners for they produce harmful gases. They contain germicides and they whiten (bleaches)  therefore care should be taken on their use to prevent spotting of other surfaces. Disinfectants,  antiseptics and deodorants are not strictly cleaning agents but used during cleaning operations.  Disinfectants kill bacteria while antiseptics prevent bacterial growth. Antiseptic are usually diluted  disinfectants. use of disinfectants and antiseptics should be controlled since they have strong  smells and their use suggest illness or bad drains. Deodorants are used to mask unpleasant smells.  They may be obtained as aerosol sprays.

Polishes 

Polishes do not necessarily clean but produce shrine by providing a smooth surface from which  light is reflected evenly. 

They smooth out any unevenness on the surface or provide a very smooth protective layer as in  floor and furniture polishing. 

General Principles in Use of Polishes  

▪ Apply to a clean surface  

▪ Use only when a satisfactory finish cannot be obtained without it. 

▪ Use the smallest possible amount to obtain the desired finish 

▪ Remove all traces of the polish 

▪ Ensure correct type of polish or polishing method is used. 

Types of Polishes  

a) Metal polishes

Remove tarnish on metals. They have a fine abrasive which provides friction to remove tarnish  and produce a shrine e.g. brasso, silvo. Some may contain abrasive powder in a grease solvent  and in some acid to remove the tarnish. 

b) Furniture and floor polishes  

They offer protective finishes which provide the surface of the furniture or floor with a thin  layer of wax or resin. The layer protects against abrasion, absorption of spillages and dirt  and also gives a shine or sheen. 

Requirements of Good Polish  

▪ Give hard dry finish  

▪ Give an easily cleaned surface  

▪ Does not mark easily  

▪ Reduces costs of cleaning and maintenance  

▪ Does not smell unpleasant 

The polishes may be paste, cream or liquid  

i. Floor polishes  

They are spirit or water based  

Spirit –based polishes contain blend of mainly natural waxes dispensed in spirit solvent  water –based polishes are emulsions in which fine particles of natural and synthetic lax are  dispersed in water. They are suitable for thermoplastic, rubber, PVC floorings Spirit –based floor polishes are suitable for wood, cork and Magnesite floorings or those  harmed by water 

ii. Furniture polishes  

They contain a special blend of waxes, spirit solvent to soften the wax. They also contain  silicone in some cases, which make the wax easier to spread, give a harder and more lasting  finish, and improve resistance to heat, moisture and sunlight. The polishes may be:

▪ Paste  

▪ Cream  

▪ Liquid 

Spray- on 

Types of furniture polishes 

Paste furniture polishes 

• Contain 25-30 % of wax. 

• May include silicones. 

• Are applied sparingly with a rag and rubbed up well with a soft cloth. 

• May give a sticky finish if too much is applied at one time and if not sufficiently well  rubbed up. 

• Leave a layer of wax as spirit evaporates. 

• Build up of layers gives high gloss in time. 

• Are suitable for antiques and other pieces of wooden furniture where the shine is dependent  on the layers of wax. 

• Also suitable for wood paneling and if not too high in silicone content for wood and cork  fillings.

Liquid furniture polishes 

• Contain 8-12% wax. 

• High percentage of solvent gives some cleaning action. 

• Are good for removal of food stains, drink rings and finger marks. 

• Should be applied with soft cloth and the resultant haze wiped after a few minutes. • Are most suitable for furniture which already has a shine. 

Cream wax polishes 

• Are emulsions of a blend of light coloured waxes in water and oily solvents. • Contain approximately 20% waxes. 

• Have some cleaning action because the emulsifying agent is usually a detergent. • May or may not contain silicones. 

• Are best applied with a damp cloth and rubbed up immediately.