You guys should go back and read Michael Yount's post on mixing it with a gallon or two of gas before adding it to you car. Listen to this man when he posts.
Check the plastic material, usually marked near the Recycle symbol. Polyethylene will degrade in a few hours, but I have not had a problem wil high density polyethylene. Look for the marking HDPE and not PE. Other plastics will probably work, but HDPE is rather easy to find.