Instead of sanding and washing, I would try washing then sanding - just brush off any sanding/dust.
I wouldn't want any soap residue or solvents playing havoc with the adhesion of my finish.
newbie here. some molds i notice seem to produce 2 separate halves that i presume you then either glue or maybe melt together...can someone give me some pointers on this process...the glue thats used, etc?