Cloth inside walls
Don't get upset yet.... I thought maybe. Wait for other posters like an older plumber that worked with the wrap. (Older than me- 62). Don't disturb any more than necessary, keep the fibers out of the air. It may be canvas, though pipe insulation in a wall sounds more likely.... If not an exterior wall, I would say the chances are slim.
Be safe, Gary
Clothes taking longer to dry?
Clean the dryer screen in HOT water if using fabric softener sheets.
They leave a residue that impedes air-flow, costing you money.
Clean the ducting in the last six months? 17,000 dryer fires annually!