Leaves, pine needles, oak tassels, maple seeds (helicopters) sticks, twigs, lichen, moss, bird nests, bird eggs, and maybe the occasional model rocket or piece of Icarus’s wings. Just name it and it can wind up clogging your gutter guards – and eventually your gutters. Your gutter guards not only must keep out all of that and more, but also still be able to let water filter through and get to where it belongs (in the gutters).