It is pretty rare, however, that someone needs to clay their car immediately following an application of a wax or sealant. Sure, you could detail on Sunday and be exposed to some nasty overspray on Monday, but that's pretty rare. Annoying as heck, sure, but rare. In the vast majority of cases, when someone determines that it's time to clay their car it's usually been a while since they waxed it. If it's been three or four months since you last wax application, there isn't a heck of a lot of wax left anyway, so what is left should easily be removed with clay or even a light paint cleaner.