Gas works really really god. that is.. REGULAR GAS WITHOUT PREMIX! lol Takes out everyhting. All foam filter oils do the same thing. basically, its almost like commonsenze. if you buy a thicker oil, its going to restrict airflow more, but trap more dirt. If you buy a thinner Oil, Itll allow more air flow, but most likley not grab the dirt as good as the thick stuff.
I've been using gas for... well a long time and it has never caused any problem. I reuse it and keep it in a plastic container ( dirt falls to bottom and I pour off the top! ) . I just let it air dry with out soap and water.
Gas will clean the filter fine, but it has 2 major problems:
1) It is toxic and will absorb through your skin. The fumes are toxic, too. Long term exposure can reportedly cause liver and kidney damage.
2) fire hazard (it's a low flashpoint solvent)
FWIW, when I used gas, I never noticed it damaging the filter or seams.
I used to use gas, but switched to No-Toil years ago. No Toil is a system with its own oil and powdered soap. The soap and warm water will disolve the no-toil oil. The no-toil powdred soap does not work on regular air filter oil, so you need the whole system (it's not expensive)
I'm a big fan of No-Toil. The filter oil is a derived from vegetable oils. Additives are added to it to make it sticky and tacky. You can clean the filters right in your kitchen sink with no harmful effects to septic or sewer systems.
With No-Toil, cleaning an airfilter takes about 30 seconds. Simply drop the filter into the soapy solution and agitate the filter for 20 seconds. A quick rinse and you’re done.
The best part is that you don’t have to handle any toxic chemicals.
I use a product which is basically identical to twin air filter solvent. It is good since you can use it like a parts cleaner too. I get all the dirt out by submersing the filter and then letting the liquid run from the inside out. This flushes all the dirt away in about two minutes. Then I get the garden hose and lightly spray the filter from inside out and when I don't see any solvent anymore, looks white, I know it is time to wring it out gently and hang to dry.
I read in a magazine that Belray foam filter oil was best since it is thick when it comes out of the bottle. It does keep a lot more oil in your filter and if you are not good at getting rid of the excess oil it can cause a rich condition in the carb. I also tried silkolene and it is very watery and is much more easily applied. I use a pan and pour some over the filter and then mop the oil up with the filter and press down on the filter to ensure even coverage. Then once that is done I squeeze it all in my hand to get rid of excess oil. The excess is easily poured back into the bottle from the pan.
Store your freshly oiled filter in a big freezer bag. I position the filter in a corner with the bottom or seam of the filter at the bottom, toward the corner. Then I seal the bag with as much air in it as possible. This keeps the filter from resting too much on the plastic of the bag. Why do this. When I store the filter in the bag, it is hung by a corner so the corner beneath the filter is able to catch all the remaining excess oil and when you go to take the filter out of the bag, this oil is not reintroduced to the filter.
Whew, that was a long explanaition.
I like both oils, silk for wet and bel for dry conditions.