One of my African Greys keeps digging (with her beak) the grout between floor tiles. Obviously I try to stop her doing so, but she keeps managing to get some when I'm not looking. When I pick her up there's often a fair few "crumbs" of it in her beak (which I try to remove). Is it harmful? The grout is long since dried (laid 2 years ago), so does this mean the harmful solvents have long since evaporated?