*The following is only a option if you can't find any other way to get them out*
Rubber is probably hardened up and has gunked and sealed itself to the metal in the lowers. A little heat from a propane torch, slowly heating it so not to warp the forks themselves, and the rubber should melt out. Scrape the rest away with a razorblade, being careful not to scratch up the inner of the lower in the process (sand and scotch-brite any scratches). That should get rid of all the old seal material.