I use MS Moly - the bullet coating spray, for coating my moulds. Stops lead from sticking and helps bullets drop out. Rapine Mould Prep is a quick drying, liquid graphite coating that does the same thing.

The moly spray sold by eithr Birchwood Casey's or Hoppe's is also good. One of these is not suitable as it wipes off easily - I just can't remember which one of the 2, is the bad one. I think it's the Hoppe's - but I'm not sure.

The MS Moly and Rapine solutions both work amazingly well.

Spraying the patched bullets with MS Moly might make for an interesting experiment as well.