If they have a non-removeable Cambrelle lining, I'd be reluctant to soak them in hot water. I had a pair of Matterhorn's that had the non-removable Gortex bootie with Cambrelle lining, and I got them soaked (in a knee high swamp) in the DDT Area in Gagetown, wore them for several hours that way (we were doing dismtd recce ptl's so didn't have spare's with me) and I found the lining never really was the same after that and the comfort level was degraded about 25-30%.