I did the same as others have already suggested. Placed them in a bucket, poured some Tide in there and added a pan of HOT water. Let them soak overnight (buckles and all) and in the morning laid them in the driveway and let the sun dry them out. Then I used WD-40 and sprayed the buckles as they were seized in place and you could not slide them to adjust. After a few minutes of pulling and pushing the material back and forth, they freed up and were good to go!