
I have two long-haired Maine Coons who can produce MEGA hairballs. I tried the Petramalt type stuff and vaseline but they hated it and I ended up having the force it down them and I think the carpet, my shoes, the walls and the cat's fur got most of it.
I tried the hairball formula food (Science Diet) but it didn't help and my vet didn't think it was a good food for them. I tried the Pounce hairball treats which were essentially little globs of petramalt-type goo coated in a treat. They didn't really like them and would leave them in the bowl for days until they realized I wasn't going to give them some better ones.
Then I found the Purina Essentials hairball treats. They are little heart-shaped semi-soft treats and my cats LOVE them. I found this out the hard way when I dumped the whole package in the bowl and they ate them all. Boy did that clean them out!

They still have some hairballs but it's a lot better using the Purina treats.