Rust inside a steel frame
I'm afraid I'm not particularly adept at bike maintenance and would appreciate some advice (again). While changing my seatpost last weekend, I noticed a bit of rust inside my bike frame, near the bottom of the seat tube. I've mentioned this to a couple of chaps at bike shops I've visited on shopping trips and they've told me it's nothing. Apparently I can just wipe the rust off with something like a scourer. The bike is in good condition but it was stored for me by a friend for about a year (in a loft/attic) and I rode it through the last winter. It was serviced after the winter.
My questions are:
1) Is there really nothing to worry about?
2) Any ideas about how to clean off rust located in this area – tying something onto a stick is the only thing that comes to my mind but I'm paranoid about it falling off and getting stuck inside.
3) If I manage to clean it off, is that it? Pop the seatpost back in and forget about it?
4) Should I just take it to a shop to be dealt with?
Thanks for your help.