Pretty much stuck looking to see what is up. IMO you need to bust apart brakes once a year up here, so much road salt. Although I think constant exposure to water will wash away brake lube (and under carriage oiling too).
Of course it could be something else. For a while my truck would make a rattling sound, like heat shield, but only on certain turns. But never any other time. ??? In the end, I got up under it, found that the shield was loose, put a band around it, and no more rattle on turns. Maybe you have similar.
2011 Toyota Camry, base, 2.5L/6MT, 200k, hers
2010 Toyota Tundra DC, 4.6L/6AT, 157k, ours
1999 Toyota Camry LE, 2.2L/4AT, 220k, his