They are a bit. Kinda wish they were a tiny bit more rigid. That said, you can have my silpats when you pry them from my cold, dead hands.

I usually push the sheet liner against the vertical side of the sink where it is flat to wash. Wash one section at a time, both sides. Takes about 30 seconds.

Though, this may be the technique you are using, and it may be a pita.

Wealthy people fly their private jets to get cigarettes, I’m not losing sleep over my baking sheet liners I’ll probably have for the rest of my life.