Originally posted by k100d is it easy to remove glass from filters? ... i've never used one
It is quite easy. Most filters have the glass held in place by a ring spring which sits in a groove. Look for the "crack" in this spring, lift one end off the groove & pry it out slowly around the full circle.
Some filters use a threaded retainer ring, you can tell this type by the two notches on opposite sides so a blade can be used like a wide screwdriver. Not having this blade I used a small screwdriver as a chisel, a few light taps were enough to loosen it.