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Cleaning
Laboratory Glassware
Why
Clean Glassware?
For several reasons it is important that all glassware be cleaned properly
before use.
- Clean glassware is essential
because small amounts of impurities left on the glassware from previous
experiments can ruin the next experiment by inhibiting chemical reactions,
catalyzing undesirable side reactions, or invalidating results of chemical
tests.
- Also, impurities or residues
left on glassware can ruin it by attacking the glass, weakening its
structure, and may lead to accidental breakage during future use.
How to Clean
Glassware
The following procedures are recommended for the cleaning of general purpose
glassware.
- Always check your
glassware for damage before using it. Remember, scratched or cracked
glassware may not be safe to use. Small cracks are likely to expand
during the application of heat to the glassware, causing it to shatter.
- Most glassware can be adequately
cleaned with water and soap solution by vigorous scrubbing (taking
care not to scratch it) using a brush of appropriate size and shape.
Some organic residues will not come off with soap solution and water
but will dissolve in other solvents such as acetone or methylene
chloride followed by a wash with soap solution and water. Your laboratory
instructor will specify when solvents other than water are to be used
for cleaning purposes.
- After washing, always rinse
the glassware thoroughly with tap water. Finally, rinse with several
small portions of distilled water from a wash bottle. Usually, three,
ten- milliliter portions of distilled water are sufficient. Rinsing
your glassware with small amounts of distilled water is necessary to
remove impurities contained in the tap water. Distilled water is
expensive to produce and should be used sparingly when rinsing glassware.
Checking
for Cleanliness
Check your glassware to see if it has been cleaned correctly. If glassware
has been thoroughly cleaned, water applied to its inner surface should
wet the whole surface evenly with no formation of droplets or dry patches.
If this is not the case, rewash your glassware until it is clean. Contact
your laboratory instructor if glassware does not come clean in spite of
your best efforts. 
Reprinted from:
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Society
for Amateur Scientists 
Sponsored by: