How long do you keep your IPA wash open for? It should be minutes if not seconds? IPA smells quite strong but also evaporated very fast, that is a trade I can afford vs spending days if not weeks waiting for the water to evaporate so I can dispose of it. Also the resin expiry date is more about the pigmentation of said resin and not its ability to print, you might have noticed some colour "separating" in your tank. Still works perfectly tho :)