I've been using NO Toil and their filters on my husabergs since what '99 I think. They make filters for all the Husabergs by the way.
If you do not know anything about no toil, then here is a little info: No Toil filter oil is bio degradable. And, you wash your filter in the kitchen sink as there is no odor to smell up the house. When you open the drain, all the dirt goes down with the water.
Now, I can already hear someone saying, well that means if the filter gets wet the oil will come off and my motor will be ruined. NOT TRUE. The oil only breaks down with their cleaner, that is also bio degradable.
Others have worried wheter or not their oil will stop the dirt, that too was my worry before I started using it. However, the mechanic at Eric's in Pasadena CA used NO TOIL on his two stroke bike, and now his four stroke bike, and he assured me that it would stop all the dirt, perhaps even better than the other stuff. So, I decided to try it, much to the chagrin of my riding partners. The first race I rode with it was a Desert Scrambles in Red Mountain, the race was 66 miles long, and for about 3/4 of the race I was in super thick dust as I had got a bad start that morning. During the race I was thinking to myself, well this is the test 0 fire for the NO TOIL.
On monday after that race as I was taking my seat off to put a plastic bag over the filter before washing my bike, I thought well this should be interesting...... My air filter looked like a dark choclate brownie! I put the seat back on washed the bike, started it up as usual, then drained the oil. I pulled the filter off and reached down into the boot with a white rag and there was NO dirt in there.
To compare, when I was using Maxima foam filter oil, in conditions described above there would always be a slight amount of extremely fine dust in there.
The NO TOIL oil will not wash out with gasoline either, unlike petroleum based filters oils.