You need this using it while you solder and specially after you get done before you turn the iron off. Leave it tinned. Amazon sells a lot of the different brands and kits. Use this brass wool ball and jab the tip in there several times often while soldering. Forget the wet sponge. The wool ball is all you'll need. You can also buy stainless steel balls you find to clean pots and pans to bolster the brass ball that comes with these ball holders. This way you don't have to dig in there with the iron tip if they don't give you enough wool.