How can I safely dispose of these materials?

Article courtesy of Smooth-On, Inc.

User safety and care for our environment are top priorities at Smooth-On and we believe that offering our customers all available information on the proper disposal of cured and uncured materials is in everyone’s best interest.

Rules for disposal may vary depending on a number of variables that include;

  1. Are you a company or individual?
  2. Is the item to be disposed of hazardous or non-hazardous?
  3. Is your disposal requirement(s) a one-time event or will it be ongoing?
  4. Amount - are you disposing of ½ pound of material or 500 lbs.?
  5. Where are you in the world? Different US states and different countries have varying (and sometimes conflicting) rules and regulations.

Disposing of Cured Materials - Some people want to dispose of cured rubber molds, plastic or foam castings.  Historically and with few exceptions, municipalities have considered “properly reacted” and cured compounds solid waste and a non-hazard that can be disposed of in a landfill.  “Properly reacted” means part A + B of a Smooth-On rubber, plastic or foam system meant to be mixed in correct proportion as directed by the technical bulletin for that product so that the material fully cures.  

If you are not sure whether or not the cured material you have can safely be disposed of in a landfill, you should contact your local municipality for direction.

Disposing of Uncured Materials - if you are looking to dispose of uncured materials that are still in containers such as liquids, pastes, powders, putties, aerosols, etc., you should reach out to your local municipality.

They may ask to review a Safety Data Sheet (SDS) for the material. SDS’s can be found on-line at  If you are not sure what material you have, contact Smooth-On for assistance by clicking here.

Your Responsibility…The Bottom Line - In all cases, you should consult your local municipality for guidance on disposal.  If you are in the USA, The Resource Conservation and Recovery Act of 1976 (RCRA) requires the user of the product to determine at the time of disposal whether the product meets RCRA criteria for hazardous waste as defined in 40 CFR Part 261. Waste management will need to be in full compliance with federal, state and local laws.  

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This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.