it's that easy.
removing the frame....it should just unscrew with either a phillips head screw driver or an allen screw. You didn't say if it was back bottle or not, but the back screw will either screw into a back bottle ASA or a back cap. Shouldn't be hard.
If you wipe the parts down with a cloth or paper towel you should be able to get gunk off.....I suppose you could polish them up with Brasso as well.