I remember putting mine in a washing machine the night before going on holiday. It melted the heel cups. Ruined my running plans as I was going to rural India with no sports stores
.
In retrospect I should not have used a hot wash. Or I could have ripped the cups out. Sounds obvious now. But I tried to mask the deformity with plasters then run in sandals. Disaster.
You could use one but just make sure it's a cold wash.
I don't any more. I soke them in a bucket. Then put them on top of a radiator. But only an old metal radiator. Not hot air. They also melt stuff.