cutting oil filter open

It might be interesting and worthwhile to share different methods of cutting the filter open. Needless to say, a hacksaw isn't the best idea because it can contaminate the filter material with shavings. The only option I had was to "chop" the filter all around with a multi-purpose painter's tool & hammer. (Like a stiff, sharp, putty knife.) There are tools available for it, but it depends what one has on hand.

I haven't figured out the best way to cut & spread the filter material yet.