I have been using those plastic tubs that you can store things in. Acetone has had no effect on them and they come with a snap on lid. So I have extremely small amounts of evaporation. I can't recall the brand name, but it is something like Sterilite? They make them in all kinds of sizes, so get the size that works for your stock. I see these tubs in places like some hardware stores, Dollar General or Alco for about 4-5 bucks. Oh yes, I soak the stocks outside as well and of course replace the acetone back in the cans that it came in marked "used".
