I have used both Bel Ray and PJ1 both are crazy sticky.
What I do is take a large freezer bag. I put the filter inside with some oil and push most the air out and zip it up. Now I can work the crap out of it and I am not wasting the oil. I just leave the bag sealed and use it again on the next toys filter.
For cleaning I have cleaner it goes in and sits then you rinse it with a hose and it just washes right out with the old oil and dirt.. if you want to get crazy you can then go back and wash with dawn and water or whatever. You can also use the cleaner in a zip lock bag as well. That way you can use it more than once before throwing it out.
I have done the bag thing for years and its great and a lot less messy.
Once cleaned and re oiled I take it out and sit it on cardboard for a night to drain any excess off.
I imagine the sprays are not recommended because they are used too sparingly. It will change the color of the filter and people may think its penetrated but it may not have as thoroughly as the oil being worked into the filter. If you use the spray just use enough. Again a bag works for this too, leave the mouth open and spray into the bag on the filter. Also realize its got a propellant in it of some form so maybe that is the argument against sprays.
This cleaner goes a long ways:
http://www.amazon.com/Maxima-70-79964-Air-Filter-Cleaner/dp/B0068EPK7A/ref=sr_1_2?ie=UTF8&qid=1464385571&sr=8-2&keywords=foam+oil+filter+cleaner
A whole range of oils available:
http://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=foam+oil+filter+oil