I'd simply remove it, ESPECIALLY if I knew it contained asbestos. IN fact, if a seller told me so, I'd use it as a 'bargaining chip' because I know what I'm dealing with. The vast majority of people out there freak out when they hear the word asbestos.
If you ordered a burger from Wendy's and asked for no ketchup (because you hate it), and drove the 5 miles back home to sit down in front of the TV to watch your favorite football team, only to find out they put ketchup on your roll, do you think they should have 'disclosed' that to you when what you were expecting was NOT what you wanted??! Now open your eyes and pretend you spent over a $100,000 for a HOME (not a burger), and found out later that there's asbestos in the house. I think that you might feel like you got screw juuuuuust a little that you paid what you did for a house with 'encapsulated asbestos'. It's not the asbestos; it's the idea that someone did what they did and didn't tell you about it.
FWIW, when I bought my home 6 years ago, we had to ASK for a Seller's Disclosure Statement. WHen we got the home inspected, the inspector noticed 'water lines' and rust on the HVAC unit, the washer & dryer, and the wooden steps. He DID say they weren't recent but he estimated the damage on the HVAC unit to be 6 years. It was rusting a little about 3" up from the floor all the way around, on almost all the previously mentioned 'appliances'. Well, the previous owners said that they have 'no knowledge' of water ever being in the basement (on the Seller Disclosure Form). THEY lived there for 12 years at that time! They knew and they lied! Three, lousy, stinking months after moving in, we got an ice storm that 'permitted' rain water to not get absorbed into the ground, thus, running into a window well and into our basement, UNBEKNOWNST to us at that time. Fortunately, we didn't have much stuff down there but we did get 2" of water!!! Yes, I don't like it when people lie to me. Had they simply explained to me why there was water, like there's a spot on the paper next to the Yes, No, and Maybes to do so, I would have been able to consider if I could 'fix it'.
When I go to sell my home, I will explain the 1 time we got water in our basement. And at the same time, I will show the Realtor and/or the prospective buyer what I did to ELIMINATE the problem. That's peace of mind. If you have no conscience and don't care, then ignore and lie.