Hi, most of the plastic mixing cups I use do not clean very well after use, especially with epoxy.
If I leave the resin inside, it becomes brittle and never detaches completely. If I clean it with acetone, over time the plastic becomes dull getting the problem worse.
So do you use any strategy not to waste too many mixing cups?
I was thinking about using a realease agent but I am worried about contaminating the resin.
Also I try to look for silicone mixing cups but found nothing in the usual stores.
Ideas?

Polypropylene buckets seem slightly better as they can flex a bit to crack the resin out and will get a few uses before being ruined.  Being flat edged, its usually easy with a flat edge mix stick to knock off any stuck bits.  

They will degrade like most other items but as long as you clean them before disposal, polypropylene can be recycled in most countries no problem.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Thank you everyone.
I wonder if someone ever thought to produce silicone containers... could it work?