This set uses one of my favourite techniques - hydro-dipping (or marbling).
With this technique, you drip special inks onto the surface of some water to make a pattern, then carefully dip a blank dice down into the water so that the ink folds around it. You then cast the patterned blank in resin to seal it.
Thanks!
No extra steps required really... the tricky part when doing these is finding a way to grip the dice in such a way that you don't mess up the pattern. I've found the best way to do this is to drill a small hole in one face and push a cocktail stick into it. You can leave this in while the die dries (pushed into some plasticine). When you remould the dice, the hole goes under the logo, so it won't be seen.
Great way to do it!