Buy some hairball medicine
Pumpkin puree works well. Just smear it on their paws and let 'em lick their paws clean.
From Little Big Cat :
- Vaseline (Petroleum Jelly). The primary ingredient in most over-the-counter hairball remedies (Laxatone, Kat-a-lax, Petromalt), petroleum jelly (or its close relative, mineral oil) can be given to the cat by mouth. Most cats tolerate it, many cats come to like it, and a few even enjoy it. The Vaseline brand is, according to my cats, the tastiest; but other cats prefer one of the flavored hairball types. Give 1/3 to 1/2 teaspoon per day. Because it can interfere with nutrient absorption so giving it on an empty tummy (at least 2 hours apart from meals) is best. Petroleum jelly is a large molecule that is completely inert in the body. It’s the ideal lubricant and “escort” for intestinal contents, because it reaches the colon unchanged. Vegetable, coconut, and other digestible oils are broken down and absorbed in the small intestine, and cannot lubricate the colon where it’s most needed.