You just need to fill the pan with enough water to cover the residue, then throw a dishwasher tablet in it (look for one which contains enzymes for a better cleaning performance) and then simmer it on ...
If your bath has plenty of soap scum or hard water stains, there's a handy way to get rid of them using a common household ...
It's unsightly, smells bad, and can affect your health. So what's the best way to get rid of black mould on silicone sealant?