WPI sells a new line of quality borosilicate glassware for laboratories. This article includes information on caring for your glassware.

Soda lime glass is a softer glass and should not be used for laboratory purposes, because it cannot endure the temperature or pressure changes of borosilicate glass, and it should not be autoclaved at the high temperatures. Most bottles are made of soda lime glass.This article deals with borosilicate glass. Do not mix soda lime glass with borosilicate glass in racks when you are cleaning or autoclaving. 

New Glassware

New glassware is usually a little alkaline. After inspecting it for clips and cracks, wash the glass in warm, soapy water and then soak it in a solution of 1% HCl or HNO₃ for a short period of time. Wash the glassware again and rinse it thoroughly with distilled water.

Why Glass Fails

When laboratory glass breaks under normal use, it is usually the result of a chip, abrasion or scratch, or because it was exposed to quick temperature or pressure changes.

• Inspect your laboratory glassware upon receipt and before use. Hold the glass up to natural sunlight and look for chips, cracks and fractures. Even tiny fractures can cause the glass to break under pressure or in elevated temperatures.
• Avoid bumping glassware against anything (other glassware, the side of the sink, desktop...). This can cause tiny fractures or cracks.
• To avoid damage to the glass, do not soak it for long periods in strong alkaline solutions.

Proper Cleaning Tips

At a minimum, laboratory glass should be free of chemical residue and grease. Depending on your experiment, it may also need to be sterilized.  Some tips for cleaning include:

• Use a soft bristle brush for cleaning to avoid unnecessary scratches.
•  Never use hydrofluoric acid (HF) to clean glass. Among other uses, HF is used as a descaler, a rust remover, a metal cleaner, a glass-etcher and a metal plating compound.It is highly caustic.
• Never use strong alkali soaps or acids to clean glass.
• Standard borosilicate glass is autoclaveable. If you autoclave the glass, vent the autoclave and let it cool slowly. Autoclave at 230-240°C. For short periods of time (after an extreme use) it can be autoclaved at 400°C.
• Ashing glass in mechanical ovens over 500ºC for long periods of time will shorten the life of your glassware.
• To test that a glass container is fully wettable (especially important when making precise liquid measurements), verify that distilled water will wet all surfaces equally.
• Wash all glassware immediately after use to remove all residues. If immediate cleaning is impossible, soak the glassware.
• Never use wire brushes or brushes with a wire core to clean glassware.
• Alconox is the best cleaner for glass. However, a non-abrasive dish soap also works well.
• Always rinse clean glassware well and follow with a distilled water rinse.
• Cidex is good biocide.
• Remove grease by boiling the glass in a weak sodium carbonate solution. Or, use acetone. Rinse well with water.
• Ultrasonic cleaning is an excellent choice for glassware, especially when it is combined with a heated solution of mild detergent.

Stain Removal

Drying Glassware

Oven drying at 100°C is best, but rack drying is fine.

Steam Autoclaving

Autoclave borosilicate glassware for 15-20 minutes at 100-120ºC. Remove all closures, clamps, clasps, etc. when autoclaving. If it is not possible to remove them, at least loosen or unscrew them to avoid pressure buildup.

You can find WPI's complete line of glassware products on wpichemisty.com. If you have questions, please contact Heidi at 866.606.1974 or This e-mail address is being protected from spam bots, you need JavaScript enabled to view it .