I've heard if you freeze them, they are reusable
I believe that it is nearly impossible.
Do not attempt to reuse a freeze plug. They are pressed in to make a tight seal and will not seal properly if reused.
Try http://www.blinky.co.nz/
I do not believe normal hairdye would work.
you get your old color back (if it is washable hairdye)
You need color remover pads. They have them at places like Sally Beauty.
If you do not use the gloves that are given with the hair dye then you are bound to have your hands died as well!
can you reuse a nickel?
Reuse
"The 3 Rs" are most commonly referred to as "readin', writin', and 'rithmatic".
Reuse is a verb (to use something again) and a noun (in a state of reuse).