How to Clean Lab Glassware Safely

Introduction

Laboratory glassware has frequent contact with a range of substances on a repeated basis and ensuring that equipment can be reused safely requires a robust cleaning process. Effective cleaning also helps to prolong the life of the products used and protects the validity of future work. The act of cleaning lab glassware for reuse is often referred to as reprocessing and can be carried out manually, with the use of automated washing equipment, or a combination of both. This article outlines the core steps required for effective reprocessing, as well as general tips for cleaning glassware safely.

"Whether full reprocessing is taking place or not, and whether it is manual or automated, there are a number of tips that can help ensure that lab glassware and plastic-coated glassware are cleaned effectively and safely. "

Reprocessing Laboratory Glassware Explained

A complete cleaning or reprocessing cycle typically consists of four stages, although not all are always necessary. These are:

1. Initial cleaning: This step ensures the removal of any adhering contamination from the surfaces of laboratory glassware, using process chemicals if necessary.
2. Neutralization: If required, this process is undertaken to neutralize the residues of any process chemicals employed on and in the surfaces of laboratory glassware during cleaning. As alkaline process chemicals are typically used in cleaning processes, acidic chemicals are generally used for neutralization.
3. Rinsing: This step removes any remaining dissolved/detached contamination and the process chemical employed from the surfaces of the glassware.
4. Disinfection: This stage is only required if the safety classification of the laboratory or of a specific process demands it. The aim of disinfection is to reduce the number of pathogenic germs and active viruses on the surfaces of laboratory glassware and, if applicable, to reduce the contamination to a degree which is accepted as being safe.

Basic Tips for Cleaning Lab Glassware

Whether full reprocessing is taking place or not, and whether it is manual or automated, there are a number of tips that can help ensure that lab glassware and plastic-coated glassware are cleaned effectively and safely. Here are 12 tips to help you in your daily work:

1. Washing machines may be used to enable automated reprocessing. Support racks on the washer must be well maintained and the support pins should be coated with a non-abrasive material to prevent metal to glass contact and scratching.
2. For manual washing, use only plastic core brushes that have soft, non-abrasive bristles. Soft, clean sponges or other wiping materials may also be used. Do not use brushes or wiping material with abrasive cleaners. Scouring pads will scratch glass and should not be used.
3. Inspect your glassware after cleaning and discard it if scratched, chipped, cracked or damaged in any way.
4. Many commercial glass cleaners are available. Follow the manufacturer's directions for the use of these products since some are corrosive and can damage laboratory glass.
5. Organic solvents are acceptable cleaning agents when conditions warrant their use.
6. Do not soak plastic-coated glassware for long periods of time as this can shorten the life of the coating. Do not allow used plastic-coated glassware to sit unwashed for long periods of time, as this will make cleaning more difficult.
7. Do not place metal or other hard objects, such as spatulas, glass stirring rods, or brushes with metal parts, inside the glassware. This will scratch the glass and can cause eventual breakage and injury.
8. Do not use strongly alkaline products or hydrofluoric acid as cleaning agents. They are glass dissolvers and can damage the glassware and eventually cause breakage which can result in injury.
9. Do not use any abrasive cleansers, including soft cleansers, as these can also scratch the glass and if used repeatedly can cause eventual breakage and injury.
10. Do not place your hands inside glassware while wearing any jewelry, particularly diamond rings, as these will score the inside of the glassware resulting in damage that could lead to eventual breakage and injury.
11. Do not heat glassware to temperatures above 400°C to burn out carbon residues. This will result in the introduction of permanent stresses in the glass that will eventually cause the glassware to break, resulting in possible injury.
12. Plastic-coated glassware should not be cleaned with harsh, chemical-grade detergents. Instead, use a non-abrasive grade detergent. If using a dishwasher or dryer, avoid temperatures greater than 110°C (230°F). Scouring pads and brushes are not recommended for use on plastic-coated glassware.

Article with input from Dr. Weigert, AK Lab and Miele.