Brakleen can be used to clean electronics, so it's quite safe, basically any electronics cleaner should work. The fix I made was two months ago, and still works with no problems. They already were once fixed on warranty, worked without problems for 6-9 months.
The drift issue is caused by dirt inside the stick's electonic components, and the fix Nintendo does is that they clean it - atleast that's what they did to my joycons in 2019.
I can't be sure, but I believe for mine Nintendo replaced the stick component as the wear and tear appeared to be gone from my sticks. I didn't take a before and after picture so my eye could always be playing tricks on me.
Good to hear this fix solution should be safe, though sadly not permanent as the sticks are just a design flaw.Last edited by cycycychris - on 01 September 2020