quite possibly anti-freeze, Check your lines. make sure your reservoir is topped up until you find the leak. you dont wanna run out of that stuff, its kinda important..

 

Could Be Big Trouble - Check the Oil for Water Contamination : How Many Miles Yr. Motor Need Details ?
Last Serviced & By Whom ?

 

yup probably anti-freeze

 

probably anit-freeze (e.g. prestone) which is exactly that color, like a fluorescent green, but how would it get into your exhaust system? could be a leak that's trickling from the radiator/engine, down your downpipe, muffler, then tailpipes? that's kind of a windy route for a trickle. hmm...