What works very well as clamps AND RARELY LEAVES MARKS/GOUGES are wooden clothspins. The key to them is to reverse the wood and the spring. Remove the spring, turn the wood over, then put the spring back so that the fat end of the clothspin is what you squeeze . The "new" clamp is about 2" - 2 1/2" deep and has reasonably good holding power. The best part is that they are cheap.