Simply apply the DOT3 brake fluid to the surround being careful not to get any on the white aquaplas coating on the woofer cone as it will make stains that cannot be removed. Apply a generous portion all the way around the surround until it has been coated thoroughly.
Allow it to sit and absorb for twelve (12) hours at room temperature. Once it has been fully absorbed and is no longer shiny and does not appear wet, flip the woofers over and apply the same procedure to the rear side of the surround.
Allow the brake fluid to absorb another twelve (12) hours. Carefully remount the woofers into you cabinets. Your done! That was easy.
This may seem like a pain in the rear, but you will have a noticeable improvement in the performance of your grand old JBL’s. You won’t be sorry. This is especially helpful if you have a pristine pair of vintage JBL’s that are all original because it will help you retain their original condition and optimum resale value. Happy listening.!