I fitted a new galv 90 chassis to mine 15 years ago, I used 2 gallon of wax oil inside and out, and although still solid , the chassis has gone quite white and sort of furry. But where I didnt wax oil it ,ie rear crossmember, it still looks clean and just duller than when new.
It Appears that maybe there is some sort of reaction to the wax oil, although this seems unlikley, anyone else notice this ?