Here is a little run down on how important it is that you take your time and do a good job at cleaning your filter, its one of the most looked over and thought of the easiest tasks, but its easily forgotten because people don't realize how bad they are dirty.
gas is the best type of cleaner for your air filter..but is it good for your filter? Absolutly not, it drys out the filter material and ruins your foam so fast.
-Use kerosene, it does't dry out your filter like gas but does the same job.
Here is what I do to get my air filter completly orange again.
1. wash it really good with hot water and soap, fill up your sink with the soap and stuff and mat it in there for awhile until you are satified its pretty clean.
2. Then get the kerosene out in a bowl and put the filter in there and mat it in there again until you think its good.
3. Take the Filter back to the water and soap, after your done wash it out really good with cold water to get all the soap and stuff and kerosene out.
4.let the filter sit out in the sun or someplace where it will get fully dried, while that is happening clean out your airbox really good with soap or something, make sure you dont get dirt and stuff into the boot because the engine will be sucking in dirt and grit which is horrible for it.
5. After the filter is dried, spray it pretty good with filter cleaner and mat it down with your hands to get it in the filter good and don't ride for about 24 hours because the filter spray needs to settle onto the foam.
6. Install the filter with some grease on on the part that will be touching the airbox to seal it.
-Don't wring out your air filter because that cracks the foam and undoes the bond of adheisive that the company puts on.
-Don't Use Gas
-Don't hurry through the steps because you want your bike to be able to breath the best it can, so give it some of your time.