Dish soap would probably be better; not as aggressive/risk of damage to alloy coatings and valve rubber (unless I knew for certain that particular kind of brake fluid and the rubber the valve is made of are compatible, I would hesitate to use it..) but all in, nice one!
I used to teach tyre fitting years ago. Dish soap is not ideal to use because some of them contain a small amount of salt and is not ideal to use when fitting tyres as it doesn’t contain any corrosion inhibitor. When a tyre is removed, if there is corrosion (and air leaks) on the bead seat of the rim, it’s always because dish soap has been used. As I had no proper bead lubricant, I just used a drop of brake fluid as that will not cause corrosion to the rim or damage to the rubber. If brake fluid damaged rubber, we'd all be in trouble!
Looking online, apparently.
The thing is, there isn't just one brake fluid, and there isn't just one rubber.. The rubber used in brake lines is obviously compatible with the stated kind of brake fluid on the reservoir lid
You say it with such certainty, like you can look at a tyre that's been on rim for 4 years and concretely declare the presence of fairy salt having rotted the rim. I reckon that's cobblers, argument for the sake of online argument, when you know full well that alloys routinely have hammer on weights applied when they shouldn't (your own pic features such) damaging the powder coat, tyre monkeys stabbing too-sharp levers into places they shouldn't, user kerbing etc and they're routinely driven on roads literally covered in salt
How else would the moisture/salt that causes corrosion get between the tyre bead and the rim unless it was there when the tyre was first inflated?
Very rare for alloys to even be able to take a clip on weight these days and even in the old days with alloys with a lip on them, they went nowhere between the tyre bead and bead lip - they couldn’t have as they would have leaked. The clip on weight on my wheel is O/E and nowhere near the tyre.
DOT5 is silicon based and hardly used - certainly shouldn’t be mixed with any other fluid. I’ve never used it. Ever. DOT3, I haven’t seen for years. Which leaves DOT4. Virtually all rubber used on a car is EPDM.
Any science behind it?
No such thing. There’s a DOT 5.1 which can be mixed with DOT 3 and 4 but not DOT 5. Because of that, some people refer to it as DOT 4.5.
