I never think to pre-dip mandrels, so flame dry is def'ly best for me! I had a container of sludge plus, but I don't think it was good for flame drying (please correct me if I am mistaken!)~ The person who used my studio before me left a small container of blue sludge, I gave it a try and it was all right~ I bought a big container of Hotline Flame Dry and is *usually* ok, I get so frustrated when the bead release breaks away~ between me getting a little better about controlling the glass and tweaking the moisture level in the container, I don't have quite so much of an issue with the release flaking away now. :)