Sarah, ours is a really old fashioned brass thing that has 2 pots and the frame turns upside down to fit the 2 sizes. (So I use one for the cheese, then the oil, and the second smaller pot for chocolate)

BUT, for one dinner we did, I couldn't use the smaller pot (cos I had forgotten to clean it, and it is brass, so looked dreadful!) so I just cleaned the big pot that had oil in it and then lined it with foil, so I knew that the chocolate wouldn't taint.....

My aunty suggests that when you clean the oily pot out, dry it,a nd then wipe round with some lemon juice and that apparently gets rid of all funny smells and tastes........