1.

Cleaning of glassware which has contained hazardous materials must be solely undertaken by experienced personal.

2.

Most new glassware is slightly alkaline in reaction. For precision chemical tests, new glassware should be soaked several hours in acid water (1 % solution hydrochloric acid or nitric acid) before washing.

3.

Glassware which is contaminated with blood clots, culture media, etc. must be sterilized before cleaning.

4.

If glassware become induly clouded or dirty or contains coagulated organic matter, it must be cleaned with chromic acid cleaning solution. The dichromate’s should be handle with extreme care because it is a powerful corrosive

5.

Wash glassware as quickly as possible after use but if delays are unavoidable, the articles should be allowed to soak in water.

6.

Grease is removed by weak sodium carbonate solution or acetone or fat solvents. Never use strong alkalis.

7.

Hot water with recommended detergents should be used and if glass is exceptionally dirty a cleaning power with a mild abrasive action can be applied, provided the surface is not scratched.

8.

During washing all parts of the article should be throughly scrubbed with a brush selected for the shape and size of the glassware. Brushes should always be in good condition to avoid any abrasion of glassware.

9.

When chromic acid solution is used, the item may be rinsed with the cleaning solution or it may be filled and allowed to stand. The amount of time should depend on amount of contamination on the glassware.

10.

Special type of precipitate material may required removal with nitric acid, aqua regia or fuming sulphuric acid. These are very corrosive substances and should be used only when required.

11.

It is imperative that all soap detergents and other cleaning fluids be removed from glassware before use. This is especially important with the detergents, slight traces of which will interfere with serologic and culture reactions. After cleaning, thoroughly rinse with tap water ensuring that containers are partly filled with water, shaken and emptied several times. Finally rinse with deionised or distilled water.

12.

Drying can be undertaken either in baskets or on pages in air or at a temperature not exceeding 120°C.

13.

Always protect clean glassware from dust by use of temporary closures or by placing in a dust free cabinet. For cleaning specific type of glassware, please refer the following pages.

1.

Pipettes
Place pipettes tips down, in a cylinder or tall jar of water immediately after use. Do not drop them into the jar, since this may break or chip the tips and render the pipettes useless for accurate measurements. A pad of cotton or glass wool at the bottom of the jar will help to prevent breaking of the tips. Be certain that the water level is high enough to immerse the greater portion or all or each pipette. At a convenient time, the pipettes may then be drained and placed and in a cylinder or jar of dissolved detergent or, if exceptionally dirty, in a jar of chromic acid cleaning solution. After soaking for several hours, or overnight, drain the pipettes and run tap water over and through then until all traces of dirt are removed. Soak the pipettes in distilled water for at least one hour. Remove from the distilled water, dry the outside with a cloth, shake out the water and dry.

1.

Remove the stopcock key and wash the burette with detergent and water.

2.

Rinse with tap water until all the dirt is removed. Then rinse with distilled water and dry.

3.

Wash the stopcock key separately. Before the stopcock key is replaced in the buretts stopcock key are not interchangeable

4.

Always cover burettes when not in use.

1.

Culture tubes which have been used previously must be sterilized before cleaning. The best general method for sterilising culture tubes is by autoclaving for 30 minutes at 121°C (15ib. pressure). Media which solidify on cooling should be poured out while the tubes are emptied, brush with detergent and water, rinse throughly with tap water, rinse with distilled water, place in a basket and dry.

2.

If tubes are to be filled with a medium which is sterilized by autoclaving, do not plug until the medium is added .Both medium & tubes are thus sterilized with one autoclave.

3.

If the tubes are to be filled with a sterile medium or if they are to be sterilized by the fractional method then sterilize the tubes in the autoclave or dry air sterilizer before adding the medium.

1.

Serological Tubes should be chemically clean but need not be sterile. However, specimens of blood which are to be kept for some time at room temperature should be collected in a sterile container. It may be expendient to sterilize all tubes as routine.

2.

To clean and sterilize tubes containing blood, discard the clots in a waste container and place the tubes in a large basket. Put the basket, with others, in a large bucket or boiler. Cover with water, add a fair quantity of soap or detergent and boil for 30 minutes. Rinse the tubes and clean with brush, rinse and dry with the usual precautions.

3.

It is imperative when washing serological glassware that all acid, alkali and detergent be completely removed, Both acid and alkali in small amounts destroy complement and in large amounts produce hemolysis. Detergents interfere with s e r o I o g i c reactions.

4.

Serological tubes and glassware should be kept separate from all other glassware and used for nothing except serologic procedures.