Spectro Filter Cleaner in spray form the ultimate time saver!
Use it with Spectro Air Filter Oil and you'll be done with big buckets of dirty smelling solvent liquids standing in a bucket... Wet the filter with SX filter cleaner and massage it through while it "sucks". You'll immediately see something happen - then you put the filter in a bucket of warm water, massage it through and the miracle happens - namely a clean filter ready for new oil.
For best results, use Spectro filter cleaner together with Spectro filter oil.