Specs: Steel frame, aluminum seatpost.

I'm attaching a picture of a strange greenish tint at the top of my seatpost collar. The bike is less than a year old, and hasn't been left in the rain. There was/still is some kind of paste on the seatpost and inside the seat tube, but this coloring doesn't seem to come off easily.

Any idea what it is, or what to do about it?

ALSO...assuming I remove the seatpost and clean everything up...should I re-grease the seatpost? will that cause it to slide down from my weight?

ALSO...HOW CAN i MAKE FUTURE PICTURES BIG LIKE SOME PEOPLE DO HERE? I seem to only be able to do thumbnails.

Well, you have the bike. You have touched and looked closely at the stain -- what do you guess it is?

As far as what to do about it, maybe ride a lot more. You would not like the alternative.

Try removing the seat again and using sand paper gently on it might work im not sure sorry lol

When your bike was assembled, grease was used to coat the post and/or the inside of the seat tube to help prevent the seat post from getting stuck due to galvanic corrosion. The greenish tint at the top of the collar is the grease staining the paint. A cleaner wax like this Amazon.com: Meguiar's A1216 Cleaner Wax - Liquid - 16 oz.: Automotive should remove the stain, and also clean and protect the rest of the frame.

FYI when i click on your image it increases in size. There is probably an internal file size limit within bike forums that only allows you to post a smaller image.

IF you want to post a huge image you will have to go to a third party file host and upload it there and then link the image through an href link. That will give you a hugeee picture that you desire to share.

Remove the seatpost (mark the depth so you can reinstall it properly), clean it and the frame off and YES, regrease it when you put it back in. If it's the correct size and you tighten the clamping bolt adequately, it won't slip.

Thanks...I just removed the post cleaned the stain with automotive cleaner...some of the stain went away, but not all. Wiped off the seat post and as deep in the seat tube as I could...then 're greased and installed....seems to holdn fine