No, never lubricate the seals or gaskets on air filters or the filter housings. It only attracts and retains dirt and you have a mess to clean up. Very bad idea!
Technically, one should neither tap dirt out of air filters nor blow them out with compressed air. I have done both and I don't know for sure that I hurt anything. But, by the book, don't do it per the filter manufacturers recommendations. There is a good chance that you will cause some kind of damage and that might wind up costing you a bunch of bucks.
I used hundreds of washed air filters over several years in all kinds of large earthmoving and mining equipment. Saved tons of money by doing so -- and never had a problem. I also had a strict engine oil sampling program going on and watched very closely for signs of dirt entry, but just never really had any trouble that could be laid to the washed filters.
I only allowed three washings per filter, after that they were scrapped. I used reputable filter dealers that had decent wash facilities and a trained staff to do the cleaning and more importantly, inspection of the cleaned elements. I also did not used washed elements in machines that were still under manufacturers warranty. Never washed nor cleaned in any way the safety elements. Always used new. By the way, I always purchased good quality new outer filters to start with, they stand up to washing better than the cheap ones.
Generally, I washed filters because I had anywhere from 25 to 250 machines or more on the project working double shift. If a guy only has one or a half dozen units, it likely isn't worth it.
There is a lot of logistics and training involved to washing filters among your maintenance crew too. You have to be careful with the dirty ones so they don't get damaged, they have to be transported to the cleaning facility, then brought back and stored carefully in a clean environment till used. It can be a little complicated for the small operator.
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