Stain on top rails

[gillsgonewild]

We removed our cover last Friday and noticed that several of the top rails had stains on them.We used the same pool cover last year and did not have this problem . I have tried several things to remove them, CLR,chlorox cleanup, muriacid,has anyone else had this happen ,I don't think these are rust stains because our pool is made of resin, thanks
I tried attaching picture but had no luck

 

[*JLS*]

Have you tried a Magic Eraser? We actually got some deck stain on our top rails (also resin)and the Magic Eraser took it right off!

 

[TSiGirl]

We use Magic Eraser also...works great for us.