This Zenith J615W had some really mushy sound due to a rubbing voice coil. The 5" speaker has a special chassis bracket, making it really hard to find an easy replacement. The cone had a slight wrinkle close to the voice coil for some reason, so I suspected the speaker may have gotten wet in the past.
Zenith spkr.jpg
I used a q-tip to dribble GC Radio-TV Service Solvent to soften the cement around the felt cover and gently pull it off to see how bad the coil interference was. I could insert a strip of paper around most of it easily but it encountered major resistance around a 45-degree portion.
Not knowing what to do next, I worked the coil in and out before the liberally-applied solvent evaporated and things seized up again. A few hours later I came back to it and the resistance was much less, so the coil may have aligned itself
I powered up and it sounded like a quality speaker again
All this after I spent $$ getting my 11" Philco speaker re-coned by Sound Remedy. Will post that one after it comes back.