I use them myself. There is however, a purpose-made MB factory special tool for pulling the boots. I looks like an open end wrench with a bend at the business end. You work it under the boot end and lift or pry up to pop the boot off. Sorry, I don't have a picture of it but I'm sure someone does. Check the "TOOLS" catalog on this site.

If you have aluminum cylinder head, be careful about unscrewing the spark plugs while the engine is too warm.