[Spridgets] Metal opening & Wiring a 3rd light

[derf]

Use a respirator or at least a dust mask with that tool.  It works
very well but it makes metal flakes and dust that will float around in
the air.
To recap, wear gloves, eye protection (goggles are better than
glasses), and some kind of breathing filter.
I like these for around $10 a pair.
http://www.uvex.us/products.aspx#/folder=104


Like DL said if you don't wear gloves you will be picking little metal
shards from your skin for a while.  I can only imagine what those
little metal shards would do to eyes or lungs.