EDIT: Sorry, this was for the OP ... not Sansui problems ... I have no first hand experience with the Foster drivers you have but, from the way they LOOK, I would say just use the dry brush that comes with RoyCs stuff to brush away any residual cat hair, dust bunnies and lawn clippings and then apply a *light* coat, let the Toluene evaporate for an hour, then another *light* coat. After the second application there should be enough butyl deposited to plug up most of the holes in the cloth. The stuff is translucent so it may be kind of difficult to do a visual but I bet you'll see a difference. If you have any doubts and used light coats you could probably get away with a 3rd go-round as long as you don't load it up too much. Of course, the SOUND is what you're after ... Break A Leg!
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