I use paste wax. Kiwi would work. Purpose marketed mould releases work. Make sure you get full coverage of all areas where adhesion of the bedding compound is undesirable.
If you use a wax, apply a thin even coating. You don't want chunks and lumps.
I use Kiwi as well, since my last can of Johnson's Paste Wax ran out. Krylon Mould Release is purpose made for such things and goes on evenly/thin.
Suggestion, pour boiling water over the area on the receiver/barrel you are going to apply the release agent to. It helps to spread the paste wax more uniformly.