Unlike those students, you don't need your target's approval for this in advance.
Why are the LEDs so bright?. I have Nanos and unos, (copies) but the on-board LEDs are far too bright. Anyone had any success in replacing the tiny 1k resistors- they are a bit too small for me to handle, although I could probably remove them easy enough. I guess once the project is completed they could be removed anyway.
Why are the LEDs so bright?.
So you can blink them fast enough to appear dim.
I cover the LEDs with some 5-minute epoxy. When you mix it really well it introduces lots of microscopic bubbles into the epoxy, and then it dries semi-opaque.