I've been using the Blitz cloth for 20 years. I wouldn't play a gig without them. 2 things: 1) wrap a small section under each string (1 at a time) & pinch - then clean the string. It will get all the gunk out from under the string & if you just rub on the top of the strings, it'll get little fiber balls on your strings - a pain to get off. 2) The treated cloth will work as long as it stays moist. So make sure you get as much air out of the bag as possible when you store it. I cut it in half & store one back in the foil closed with tape for when I use up the other half. I've used it on Guilds, Gibsons, Fenders & Epiphones with no adverse on the finish.

I have been using this product for about one month now. It amazes me how much oxidation comes off acoustic strings. Be careful what you touch after using this product as the oxidation "grime" gets on your fingers. Just wash with soap and water.