If they are not plastic, and you are worried, do what CA did and Vaseline them. No Worries.
Originally Posted by Nordic_Kat
Please clarify re: "aftermarket valve caps". Are these one and the same as the caps sold under the P/N 36 11 0 009 840 that are available from BMWUSA?
Also presumable you check your tire pressure more often than every 2 years.
Deep Sea Blue
6 Sp Manual
BMW CCA #392316