DUDE Wipes Fragrance Free On-The-Go Shower Wipes, Extra-Large and Thick Cleansing Body Wipes for Travel, 1 Pack (8 Count), Infused with Vitamin E and Aloe

I use a shower wipe (something like this) when I have to be around other people after a sweaty run. If you need to carry it on you, you can buy something individually wrapped, or just put one in a ziploc baggie.