Logitech G303 notes:

Use black tape to cover LEDs
Plug mouse in to see light leakage
There's a light tube that connects the G logo at the top to a LED at the bottom

scroll wheel:

To get scroll wheel out, push out on both the left and right pieces preventing it from leaving
To get the wheel out of the trap of the metal bar, rotate it as you pull it out
Use heavy-duty scissors to unwedge the metal bar from the plastic thing it's threaded through
Remove the metal bar!
Before reinserting mousewheel, stack some earplugs or foam tips under the wheel assembly to avoid pushing the assembly in and breaking it
Use small - screw to stretch apart the wheel holder to jam the wheel back in