I recently attended one of the clinics on cleaning and maint. at the local dealer (always looking for ways to get out of the wife's dreaded to do list) and the subject of boot marks came up. The Sales Mgr. who was giving the clinic had a product called Road Rub that he recommended. It comes in a stick deoderant container and you extend the stick slightly and press the stck firmly against the chrome and rub. I used it on a boot mark and after rubbing for about 15 secs. the mark was gone with no damage to the chrome. I don't know how much rainsuit is on the chrome but this might work.