Just got a newsletter from Colour de Verre about priming their molds. They have two suggestions for what works best with their molds. There’s Primo Primer or MR-97 spray. Both have their advantages but if you decide to go the spray route you can’t go back. I have personally used the spray on my Colour de Verre molds and I use Primo For other slumping molds and kiln shelves. I do also use Bullseye Shelf Primer. What’s most important is that you treat your molds well and with tons of reapect so they will last forever.