I had 6 old WWII-50's era rifle slings that were all oil soaked. A couple of days ago I decided "fook it".....into the washing machine they go. I set it to warm wash/warm rinse and used twice as much detergent as normal. After they finished in the washer, I laid them neatly on the coffee table and turned on the paddle fan for about a day to let them dry. They dried and looked great. Now they look and feel like normal slings that have a little age on them.