Got the same, took a pair of scissors to them to make shorts. That could well have been almost a decade ago now, they’re still waterproof.
I don’t actually wash mine very often just leave them to dry out in the garage until the next time the weather looks minging.
One think I keep intending to do is buy some braces for them to try and keep them up, the fit is a little odd (YMMV) and I find I have to pull the waistband halfway up my torso and pull the draw-cord quite tight and they’ll still slowly work their way down occasionally leaving you with a baggy crotch that can catch a saddle if you’re not careful…
And yes, DPM shorts do look a bit ‘special’ at least until covered in mud…