I would see no reason why they couldn't be cleaned. Maybe soak em in some strong vodka or everclear. Or even very hot water. Can't really do much harm to try if they are already close to being on their last leg. I say go for it. Why not?
However, after just now reading a review, reviewer said they don't function the same after a dry burn.
Looks like they are only a couple bucks so I say it's no loss to try cleaning them.