I'm not exactly doing pro photography here; please forgive me. My baby monitor is mounted in a corner. It shines bright IR at night, and the walls are highly reflective, and I can barely see into the crib because the exposure is destroyed. I've tried a few things, including black sticky notes which might as well be white, blue painter's tape that is currently on the wall because it's better than nothing, and covering some of the emitters so they'd shine on the wall less, which maybe I didn't do right but it didn't help.
I haven't yet tried my black t-shirts, but I'm not hopeful. Is there a cloth, tape, or something on the market that is dark on the IR spectrum?