If external ear canal infection is the problem, this is not a new issue.
Good discussion of the issue:
Effect of Diving and Diving Hoods on the Bacterial Flora of the External Ear Canal and Skin
DAN recommends half and half white vinegar and rubbing alcohol.
Back during the Tektite program, in 1969, there was a lot of problem with middle ear infections, a protocol of a few drops of mineral oil in each ear prior to diving and a post dive wash was developed.
While Vinegar/alcohol is good, what we used for earwash on Tektite was equal parts of 15% Tannic Acid (15 gm. diluted to 100 ml), 15% Acetic Acid (15 ml diluted to 100 ml) and 50% isopropyl or ethanol (50 ml diluted to 100 ml) in a wash bottle. On Tektite we used ethanol because we had a bunch in the lab for pickling specimens.
If you leave a wash bottle full of solution in the sun (e.g., on the dash of your car) it feels so good after the dive.
If you have access to any High School or College chemistry lab you can make it. Or you can likely get a pharmacist to make it up (get your Doc to write it out as a prescription) or just get the stuff you need from any Chemical Supply company
1) Tannic acid (crystals), weight out 15 grams, transfer to a 100 ml volumetric flask and fill with water.
2) Acetic acid (liquid) put 50 ml or so of water into a 100 ml volumetric flask, slowly add 15 ml of glacial acetic acid then dilute to 100 ml with water.
3) Dilute an appropriate volume of alcohol with water so that you get 100 ml of a 50% alcohol solution.
Combine equal parts of the three solutions (in this case 100 ml each to make 300 ml of Tektite Solution).
Mineral oil in the ears before the dive, and Tektite Solution after. I've done this since '69 and never had any problems with my external acoustic meatus.