Hi,
I'm a newbie here, and cat crazy !
We had a cat for 19 years, and she would get furballs blocking her stomach occasionally, despite brushing her regularly throughout the spring and summer months.
Vets here recommend giving a cat 10 millilitres of freshly pressed pineapple juice, once a day for 5 or 6 days, dribbled into the cats mouth from a syringe (without needle !). Our cat wouldn't drink it willingly from her dish ! The pineapple juice apparently causes the fur ball to naturally disintegrate. It certainly worked with our cat. Please note, tinned pineapple juice will not work, it has to be pressed from a fresh pineapple.
I hope this may be of help.
I have managed to get our new cat Misti used to being combed on a daily basis, so hopefully the pineapple juice will not be necessary, although it wouldn't surprise me if she laps it up from her dish, she enjoys eating quite a variety of raw fruit and vegetables, although our vet has told us to keep her away from banana, prunes and raisins.