Every time I use any type of rust remover or converter, I get a hard yellow residue. I’ve even tried it on new metal, & get the same result. The typical white powder that forms comes right off, but there is some sort of hard yellow residue that forms. It is hard to get off. Wire brushes take forever on that hard stuff. Should I just leave it on? If not, how do I remove it? I have it in crevises where I can’t grind. Am I doing something wrong? I’m in FLorida, so I know the temperature is good, but maybe there is humidity inside of the shop?