Windshield washer fluid to load tires?

[flingwing1969]

RimGuard is the best (for maximum weight), but is the most expensive option.
RimGuard is not available in many areas, is installed by dealers, and makes a sticky/gooey mess if it leaks, or must be drained.

Rimguard is indeed messy and sticky when you get a leak. Anything you load a tire with is also going to make if a bit more difficult to plug a leak (tubeless) due to the moisture in the tire - just something to consider - not something to prevent one from loading the rear tires as it is much less expensive (unless you use Rimguard) than buying wheel weights.