How to Clean Electronic Plugs and Jacks

I use W-d40 and/or isopropyl alcohol with great success. For the W-d40, you want to use it outdoors. Both are much cheaper that what he's got. Also some mineral oil such as baby oil on a cotton swab works well too.

I use first the WD-40 and then the alcohol, to minimize residue and later sticking of dust. I also commonly use a dental pick (I keep my iPhone in my shirt pocket, and it frequently finds twigs or metal chips), and since I am considerably older than the young fellow, I nearly always use a jeweler's loupe.

I am a bit offended calling the dust remover "canned air". There is no air in the can! I do also use (real) filtered compressed air from a respectable distance.

Battery clips are commonly either oxidized and/or coated with residue from a leaking battery. Those require the dental pick and sometimes a fine emery cloth wrapped around a small flat screwdriver.

I use CorrosionX. It has kept a fleet of 20 sigma samplers alive for 15 years. It is clearly the best product I have used for this purpose. Nothing cleans up contacts like this.