I bought a 301a about a month ago. I love sewing on this machine. I cleaned it using sewing machine oil and a soft rag, oiled the heck out of it and it just works wonderfully. The only problem is that there are, what I think, nicotine stains in all the little corners etc on the machine. They look ugly and don't affect the mechanics of the machine but I don't know how to get rid of them. Any advice on how to get rid of these would be welcomed. Thanks.