A DIY method that requires a bit of planning this is as follows:

Take an empty butter container or Tupperware dish.
Fill 1/3 of it with liquid body wash
Freeze it
Fill the other 2/3 with water
Freeze it

Take this dish and a small towel to work with you.
Put the dish in the freezer at work.
After your workout, rub yourself down with the soap side to lather. Follow up with the water side to rinse. Dry off with the towel. It will clean you up and cool you down.