Troubled by brittle plastic? Having been in the plastic injection-molding industry for many years, I can tell you that most resins (that’s actually what plastics are) absorb water over time. If you put the plastic, sprue included, into a plastic bag along with a bit of water in the bottom of the bag (the amount is not terribly important — you can experiment), in a couple of days it will absorb a bit of the water and usually will become less brittle.
Tip submitted by:Paul NadeauBraintree, Vermont