Hi everyone,

I have some novice questions about rust. I just picked up a 1985 Trek 560 (Reynolds 501 main tubes, True Temper stays, I think) on CL. It looks to be in great shape, few chips in the paint, had to cold-set a bent derailleur hanger, but really excellent condition otherwise. (Stock components except Shim. 600 RD and 105 brake levers, 100$, for those curious about such things. Fair price?).

Now that I'm really going over it closely, I see tiny spots of rust at the juncture between lug and tube. They are too small for my photography skills. There is no visible damage to the paint, yet there is a tiny rust spot. My instinct tells me it must be coming up from under the paint, but how? There are a couple on the head lug and a couple at the base of the down tube. (BTW I looked into the seat tube and there is zero rust visible inside).

What can I do about these rust spots? Should I do anything about them? I bought the bike to ride it.

Also: can anyone explain what is most likely to have caused this issue?

One other question: There is no other rust whatsoever on the bike except for this weird raised accumulation of grime under the cutout for the seatpost clamp. It seems to have rust as one of its ingredients, but as I laboriously (and without total success) scrub it off, I get clean paint underneath. Any thoughts about that? There were similar accumulations on the chainstays (as if deposited by spray from the tire), but they were gray without any rusty color. These accumulations are very hard and difficult to scrape off. More like plaque than dirt.

Thank you, I am really enjoying this forum. I did search around for rust info before posting but the oxalic acid baths etc. seem like overkill given my situation.