I have a board I'd like to access the test points on (see image). But they are covered with some kind of black/transparent protective material.
Carefully scratching it with my knife leaves traces on it.

I don't want to remove the heat shield if not absolutely necessary and everything has to stay functional.

Is there any non-destructive way I can uncover the test points with DIY methods?
Or am I out of luck?

 

From your photo, the black border looks like an RF shield sealant. The shiny metal likely forms the shield itself. Test points beneath remain inaccessible without shield removal. Surface cleaning alone will not expose them. Pads beside the shield are more promising. A fiberglass scratch pen is helpful for precise material removal. Magnification greatly reduces accidental copper damage. For more info, you can see this blog about conformal coating

 

I use a fine tip probe to reduce the needed cleaned surface TP area to a needle point. A exacto knife blade tip usually works for most coatings.
https://www.fluke.com/en-us/product/accessories/test-leads/tl910

 

there are piercing extensions for test leads that fit over regular DMM leads. this allows you to test many things that would be inaccessible for regular probes. (they can go through the coating or even jacket of the wire or cable)

 

Hello,

You can use the probes that @panic mode showed or simple sewing needels:
https://forum.allaboutcircuits.com/...-sewing-needles-as-my-multimeter-probes.1942/
You can also use needles from a sewing machine, those have a thicker piece to hold.

Bertus