For a while I was using the type you can buy at GC that comes in various sizes and since iodine is commonly used to make/preserve black pigments on fabric, the iodine will rub off and leave some purple color on the corners of your synth that make contact with the cover itself. Make sure you use white covers. Although the purple is hardly noticeable, you will be bothered to some degree by it if you are a perfectionist. I myself don't mind because my Lunar Impact Whitewash Voyager is mackin and I think little things like the faint purple marks on the corners add character, but I know some owners won't be as accepting.
I hope that helps someone. Enjoy your white voyagers!
--Spitfire
