Which Key Is It?

How can these

and these

help you in the classroom?

Well... I recently colored coded all of my classroom keys.  I put a little dot of nail polish on each of my keys.  I put the same color of dot on the cabinet etc. that the key fit.  Now I don't have to go searching for which key goes with what.  I quickly look through my keys and match up the correct colors and can open up anything locked much quicker!