Standard Operating Procedures

Cleaning Laboratory Glassware


This document describes how to clean all sample preparation glass and plastic ware.


You will be using a strong soap (micro-90) and very high temperatures. You should wear gloves to protect your hands from the soap. You should also consider wearing a lab coat to protect your clothing. When using the muffle oven, wear protective gloves if the glass is still warm. You are expected to have read the muffle furnace SOP.

Terse Procedure

  1. Wash dishes with soap and water
  2. All debris, oils, sharpie should be gone
  3. Rinse with tap water
  4. Rinse with DI water
  5. Dry in hood
  6. Wrap or top with foil as appropriate
  7. Bake in muffle as appropriate
  8. return clean dishes to appropriate location

Cleaning Glassware

  1. Remove any tape or foreign matter from the glassware and rinse if needed.
  2. Place glassware in a tub of Micro-90 soapy water. Difficult-to-clean glassware may need overnight soaking and if soaking, ensure the entire piece is covered with soapy water. You may also choose to soak if you are short on time. If not soaking, proceed to next steps.
  3. Scrub as needed the inside and outside of glassware with brush or sponge. 
  4. Rinse thoroughly with tap water.
  5. Rinse well with deionized (DI) water.
  6. Place glassware on drying paper in the gray bin located in the fume hood and allow to completely dry.
  7. Do not bake graduate cylinders or sintered glass filters
  8. Once dry, cover with foil and bake in muffle furnace at 500 °C. Make sure to read the muffle furnace SOP and fill out the sign-in sheet.
  9. Return glassware to the appropriate storage location.

Cleaning Bacterial Denitrifier Sample Vials

The bacterial denitrifier method sample vials require a special cleaning method because of the oil used to lubricate the septum on the autosampler.

  1. Wear thick protective gloves that will withstand broken glass abrasion. Remove the crimped aluminum ring using the removal tool. Empty vial contents into "high-pH waste" container. If the glass vial breaks, place glass pieces in broken glass container after emptying liquid into high-pH waste container.
  2. Cover the bottom of a RED dish with 100% Micro-90 and cover vials with hot water.
  3. Completely submerge empty vials, make sure most air is out of each vial and soak for 10-20 minutes. 
  4. Transfer, and completely submerge the vials into the second RED tub of soapy water.
  5. Clean the inside/outside of the glassware thoroughly with a brush/sponge. 
  6. Rinse vials thoroughly and feel with bare hands for grease. If grease is still present, rewash the vials. If they feel clean, continue from step 4 as with normal glassware. 

Cleaning Plasticware

  1. Follow glassware steps 1-6.
  3. Return plasticware to the appropriate storage location.

Broken Glass or Plastic

If you break any glassware or plasticware during this procedure, make certain all broken pieces are put into the broken glass container.