Take an old pot, one that you don't necessarily need anymore and boil water.
Then once the water is boiling, stick them in the water for a while.
This will open the pores in the plastic so it accepts the dye.
Third you poor in the RIT dye. Here is the link to their website,
I don't know if you can buy online but I know like every craft store
has it and I just got mine at Walmart. http://www.ritdye.com/home.lasso
Fourthly you remove the goggles from the water and dump the dye in.
Make sure you turn the stove down a little bit so it's not so hot, and
also STIR THE DYE VERY WELL! Make sure there are no chunks.
Fifth you stick the goggles in and wait until they appear to have
the color you want, then leave them in for about another minute.
Finally remove the goggles, rinse them extremely well and enjoy!
and look at my pics to see the ones i dyed