How to clean cash coins

Should these coins be cleaned?

I have foolishly decided to start yet another blog. This one is called Oriental Cash, and I will be posting there on subjects having to do with all the cash series that I collect and study, not just my specialty, Northern Song Dynasty. My initial post on Oriental Cash is called Care For Your Cash, and is all about cleaning cash coins. I have recently had several inquiries about this topic, and so I've decided to republish an article I wrote back in 1991 on this subject. Click on the hyperlinks above to visit my newest blog and read about how (and when) to clean cash coins. Thanks for visiting!

宋代铁钱监、夹锡钱监一览表 (List of Song Dynasty Mints for Iron & Tin Alloy Cash)

I have started a new blog, Northern Song Cash, where I am posting new research and translations that I am doing in preparation for a new edition of Northern Song Dynasty Cash Variety Guide. I want you to have as much of this new information as soon as possible. Because it was the least covered in my original catalog, I am starting with the iron coins of Northern Song, utilizing the excellent variety catalog Liang Song Tie Qian.

Please GO to my new blog and see what you may find helpful in your own collecting and research. My first post in the new blog is a list of Northern and Southern Song Dynasty mints for iron coins. There is also a keyed map of the 89 known mints that can be downloaded to your computer and printed. There will be posted images of Northern Song iron coins from my reference collection, together with the rubbings and commentary from the Liang Song Tie Qian translated into English, as well as the physical specifications of each variety.

Please take a look, and do not hesitate to comment on whatever you see there. My new variety guide is a public "work in progress," and perhaps some of you can help me as much as I can help you.