What’s asbestos look like on heating vents

It's not really that serious in most cases. In tile or siding, it isn't a hazard unless it is broken down, generating dust that you are breathing. Even then, a lot of tile is like 1% asbestos. If you can get it up without breaking it too much, you're basically fine.

Pipe insulation that is soft is more of a problem. You can probably do it yourself if it's a small amount. It may very well be illegal though. Get a respirator like this http://www.amazon.com/MSA-Safety-Works-817664-Respirator/dp/B0009XW3ZS, take a heavy plastic bag, tape it around the insulation so it's mostly sealed, and then spray it down with water so it's saturated and won't generate dust. Then remove it, dousing with water as needed. Seal it up in the bag and dispose of it lawfully.

I was an asbestos abatement hygienist for 3 summers, and I took airborne fiber readings of thousands of hours of removal being done. Although negative air containment systems were in place on those jobs, I had probably 10 concerning readings out of thousands.

Asbestos is like smoking cigarettes in my opinion. One day isn't going to hurt you. Every day for 5 years will hurt you.

AFAIR, asbestos mastic is much more likely with tile (which may itself contain asbestos) - I would not expect it under carpet, other than as a remnant of a prior tile job (no sign of that here.) And, as you have noted, it doesn't look like it.

While you could engage full paranoia (as the folks that make money from it like) and have it tested, you can probably remove it without too much concern, and if it's "gummy" you might want to take a "solvent and wipe up" approach anyway, which would minimize anything getting in the air.