Yeah, the walnut hulls are used as a dye but there is still an odor to them (and any of the other dyeing products). Dye your traps a month before the season and hang them somewhere to air out. Since you're primarily going to make water sets it won't matter as much, but it doesn't hurt either.
"Knowing when to shoot and when to wait is one sign of maturity in a bowhunter. Be patient and pick your aim point carefully." ~ Randy Ulmer
"I suppose it's the way of hunters. We are very odd fellows." ~ Peter Hathaway Capstick