I keep a spare housing on hand so I can quickly swap it when changing the oil instead of having to clean the one that is on the car right away. When you purchase a spare one from Volvo it does come with a filter cartridge so it isn't a big expense.

Anyway, my point is that if you have a second housing you can take it to the plumbing department of a hardware store and purchase a rubber coupling that fits tightly on the end. Squeeze the coupling onto the filter housing on the car, tighten the clamp with a screw driver and it will then give you something to grab onto so you can twist and loosen it off.

This is along the lines of what I'm talking about. Mine cost about $5.

http://www.123ponds.com/avp-rc75.html

Hope this makes sense and helps!