Can You Clean Plastics in a Glassware Washer?

Lab glassware washers offer an excellent solution for laboratories that need to clean dirty labware including beakers, test tubes, Erlenmeyer flasks, cylinders, and BOD bottles. Technicians may be unsure whether dirty plasticware can also be cleaned in a glassware washer, leading them to hand wash the equipment which can be extremely time consuming. Lisa Choplo, Application Specialist at Miele Professional, addresses the most common concerns users have about cleaning plastics in a glassware washer.

1. Will plastic containers fall off the injectors during the cleaning cycle?

Plastic containers typically will not fall off injectors during a cleaning cycle as well-designed glassware washers have water coming from multiple directions to balance out the force. For example, water coming from the spray arms will be moving downward while water in the injectors move upwards. This ensures a proper balance to keep plastics in place on the injectors and eliminate excess movement. If in doubt, or when cleaning very small lightweight items, an overlay can be placed on the items being cleaned to hold them in place.

2. I’m worried about plastic containers melting in the glassware washer. Are there temperature guidelines?

The type of polymer that comprises the plastic determines the physical properties, such as the melting point and deformation temperature. This information can be easily found to determine the optimal wash temperature for the polymer being cleaned. Most washers have the ability to heat water up to 163° F (73° C) or 200° F (93° C) and temperature settings can be adjusted as needed based on what is being cleaned.

Users are encouraged to read the product literature and check the plasticware for temperature resistance (the manufacturer can be contacted for this information) before washing plastics for the first time to set the proper temperature. In fact, many washers are pre-programmed with a wash cycle to clean plasticware at lower wash temperatures.

As a general rule of thumb, if the manufacturer’s instructions state “unable to autoclave,” the washer should be adjusted to a lower temperature setting to avoid plastics melting. A glassware washer provider should be able to provide application support and assist in the machine’s programming to avoid melting or distortion.

3. Are there any drawbacks to washing plastics in a glassware washer?

Yes. Plastics usually will not come out bone dry when cleaned in a glassware washer, or any other automated washing device, and users must tailor their expectations. There is also a chance of plastics discoloring. However, the benefits of having an automated process, specifically a glassware washer to provide clean containers for testing, analytics, and research, will, in most situations, outweigh the drawbacks of discolored plastic.

4. What about disposable plastics?

Glassware washers also have the ability to clean plastic disposables such as beakers, bottles, or vials. By washing disposables just once, laboratories can cut waste by 50%, resulting in less money spent on disposables and a better environmental solution, all by turning disposable plasticware into reusable material.

5. Are there any other benefits to using a glassware washer?

By utilizing a glassware washer, laboratory staff will feel confident knowing their plasticware is being cleaned effectively, every single time, which is more difficult to achieve with hand washing. Hand washing plastic can be unreliable and staff won’t be able to determine if plastics have achieved a validated clean. Washers can be programmed to meet wash parameters for critically clean results, whether cleaning glass or plastics, a factor that is beyond human control.