I've got a couple speakers that need work: 1. A silver Vox Bulldog Alnico - no resistance reading - totally dead. Would it be worth it to re-cone? 2. Marshall Black label (Celestion?) from a mid 70's combo. Distorts when driven hard. Can this be corrected through re-shaping the voice coil with heat or something, or is it time to re-cone? I've got a (working) mate of each of these in a Marshall JMP combo. I'm thinking of reconing the Celestion to get the Marshall back to stock. Then sell the vox's or put em in a 2x12. Worth the $$ and hassle?