First of all, get them tested for asbestos. If they are asbestos, don't remove them yourself. Either get an asbestos abatement company to do it or "encapsulate" them with mastic.

Asbestos dust can cause a cancer called Mesothelioma, usually decades after significant exposure. I'm no expert, but I'd think an N95 mask and a vacuum with a HEPA filter should do the trick. Dampen everything so there's little dust.

Asbestos wasn't used in tape products like that shown in the photo after 1981 +/- If your home was constructed after that, you don't likely have a hazard. That said, I think you'll be best served to assume it contains asbestos, keep the existing tape in place, and seal over it with either UL-approved foil tape or mastic designed for duct sealing.

@sktn77a: Thanks for your help! Can you please elaborate a bit more about how to ""encapsulate" them with mastic.? Thanks!

@Charles Ross Homes: The house was built in 1937 and according to the contractor friend of ours, it does seem to be asbestos tape.. :(

While it's good to be aware of hazardous materials and to take proper precautions to minimize exposures, the potential exposure to air-borne asbestos fibers is pretty minimal--provided you don't remove the tape. You can simply apply UL-approved foil tape or mastic on top of the existing tape as needed to cover the tape and seal the duct.

And be faced with future asbestos disclosure requirements in the future.

Given this small amount of asbestos tape if this were my house I would remove it myself. I would put on an N-95 mask, spray the tape with water until it it thoroughly wet and peel it off. Then clean and dry the surfaces and apply the Nashua duct tape.

Federal law doesn't require sellers to disclose whether their home contains asbestos or vermiculite, although state laws may. That said, the particular material hasn't been tested to confirm whether it contains asbestos. It's a lot less expensive to presume it contains asbestos and treat it in situ with mastic or tape.