I recall reading that some formulations of video tape around in the 1980s actually have quite a problem with the binder, resulting in the oxide coating wearing away from the backing. Contrary to what most people would think, tapes from the 1970s have often fared much better.
There may be a fancy (and very expensive!) process to provide a temporary fix, but it's probably only something that would be done by the big pro outfits to salvage very important material.
One dodge I've heard of people using is to "wipe" the tape. It involves getting inside the VCR and winding the tape end-to-end a few times while gently holding cotton buds against the tape to remove the loose coating. There's the problem that if the oxide comes away that parts of the tape may become unwatchable, or at least display a larger number of "specklies," but it might clean it up enough to allow a single pass to re-record.
It might still be necessary to stop the dubbing at convenient points and clean the heads and guides before continuing. The result won't be perfect and is not guaranteed to work, but if the tape is unwatchable now anyway, it's worth a try.
