Standard car brake maintenance practice is to spray brake cleaner on the disc and pads anytime you touch them or are working around them with anything oily even if you don’t touch the brake parts. In my brief time with bike disc brakes reading maintenance tips, the bike crowd seems less hyper about clean brakes then the car crowd which does not make much sense. Car brakes are rarely called upon for max force (unless its a race car) and the temps car brakes hit even on the street make them kind of self cleaning whereas bike brakes are often operated close to max and seem like they’d be more sensitive to contamination and have less room for degraded performance.