this is what we have been dealing with on a daily basis from our barefoot-loving Island children:

on the Island we are surrounded by poplar trees (also called cottonwoods)
Poplars are prolific in their output of organic matter. every spring, first come the purple worms (seed pods) staining the sidewalks:
(image via)
and then the sticky buds (what we call them- resinous seed pod cases) and then the fluff (i'll post pictures in a few weeks- just wait!!) they are beautiful trees and interesting in their output- but hell if you are trying to keep your house or clothes or feet sticky bud free. (here's a cool post with lots of botanical info about the tree)
if you look at the photo above, all that black goo on Asa's feet is poplar resin that has to be removed with rubbing alcohol!! they stain your clothes if you come into contact with them (many Islanders have yellow spots on the bum of their pants from the sticky buds) Asa and Maxine insist on going barefoot whenever they're outside, but i don't want them in the house with their feet like this so it is a constant battle of washing the STICKY BUD FEET!!
but, thankfully, it lasts for only a few weeks. and also thanks to my man for discovering that rubbing alcohol will remove the goo!