Ok if its anything of any value it "should" have a hall mark of sorts.
However its filthy, Leave in in some brown sauce for a few hours then clean it, if its still not clean enough either repeat it with fresh brown sauce or leave it to soak for a couple of hours in cheap and nasty full fat coke.
That should clean it up![]()
Harpic toilet cleaner should also do it,might dissolve it though if left on for to long
