In the previous thread, someone suggested that it is out-gassing. If you do a search for that word, and the word plastics, you will find that you are not the first person to experience this. There seem to be a lot of suggestions out there for how to deal with it; whether any of them works is another matter. If it is out-gassing, it isn't obvious how a solvent will help.
One suggestion that comes up is to heat the plastic (put it in the sun, use a hair dryer, etc.), presumably on the theory that this will promote the escape of the gas. Maybe
Bookmarks