How do I remove old caulking?

Use a box cutter to remove as much as you can, then a single edge razor blade to remove the rest.

Score it with a sharp blade (box cutter, carpet cutter, razor blade, etc.) and then scrape and peel away from the wall and the vanity. https://www.thisoldhouse.com/how-to/how-to-caulk-around-tub There are also instructional videos at Youtube - search under "how to remove old caulk."

Judy...Lowe's or Home Depot have liquid to make it easier to remove too.

I use an old toothbrush sharpened to a point to keep from scratching countertops, then single razor blade to finish

Box knife to score, plastic putty knife and perhaps a heat gun, or hair dryer

Thank you for your help.