  Certain cosmic strings that occur in GUT models such as $SO(10)$ can carry a
magnetic flux which acts nontrivially on objects carrying $SU(3)_{color}$
quantum numbers. We show that such strings are non-Abelian Alice strings
carrying nonlocalizable colored ``Cheshire" charge. We examine claims made in
the literature that $SO(10)$ strings can have a long-range, topological
Aharonov-Bohm interaction that turns quarks into leptons, and observe that such
a process is impossible. We also discuss flux-flux scattering using a
multi-sheeted formalism.
