have a dedicated shelf
I have a designated pot melt shelf. It is really hard on the shelf and sometimes can even remove small chunks out of it. Give your shelf more coats of primer and you should be able to not have any “surprise” chunks. I do about 10-12 coats when I do a pot melt.
And FYI, any time you put black or royal blue into your pot melt…expect that the whole thing will turn out either black or blue…the colour is just too strong and overwhelms everything!