The serrated jaws on pliers can mar wood, cut into plastic and permanently scratch brass and chrome-plated plumbing fixtures.
To prevent these damaging bites, make small muzzles for each jaw from an old leather glove. Simply cut two fingers off the glove and slip them over the jaws. Be sure that they're long enough to cover all the serrations. To prevent the fingertips from slipping off, tack them in place with hot-melt glue.