1970 GS Radiator Overflow Bottle. GM Clear top. Early 70 build cars had this type of overflow bottle. Used driver condition-- Has rust stain on top from proximity to the fender. Comes with both GM hoses attached. as well as corect mounting screws-- $40 plus shipping from CT. 203-272-7103 or email ros6872@hotmail.com Lots of 70-72 Skylark GS parts-- please contact me with needs. www.ros6872parts.com Thanks for looking!
The stain works it’s way into the pores of the plastic so it’s never going to be perfect. Just don’t use anything corrisive. I have cleaned them up pretty good using simple green.
Rubbing compound may help a little bit also. Not sure of any way to make them look new again. Wish I did though!!!
The OP is based in CT and has a ton of stuff. It might be a good idea to call or email him directly as I know he's not on the board that often. Just a suggestion.