Preparing plastic resign sprues for modelling and painting.

Good Model preparation before painting (beginners)

librarium-online.com/2008/03/04/how-to-prepare-resin-models-for-construction-and-painting

Note especially this...

"1. Washing
Clean the parts thoroughly with a mild soap in lukewarm water. The reason for doing this is to make sure all traces of mould release fluids are removed. It also gives a very slight abrasion to the surface of the model that will help with paint adhesion."

Thanks to Librarium-Online.