Grime hides in your baseboards, often sifting down—and piling up in—that little gap between the board and wall
. Try acrylic painter's caulk to close up the opening, Mills says. Use your finger to push it in, creating a smooth line. Once it's dry, paint it to match the baseboards. No one will notice it's there, but it will save you serious clean-up time over the years, he says.