  We present the first results for the sputtering of grain mantles and cores
obtained with self-consistent multifluid hydromagnetic models of C-type shocks
propagating through dusty media. The threshold shock speed for mantle
sputtering is about 10 km/s and is independent of density. The mantles are
completely vapourised in shocks with speeds of 20-25 km/s. At such shock speeds
core sputtering commences and gas-phase SiO forms. Core destruction is not
total in any C-type shock because grains are not completely destroyed in shocks
with speeds near the minimum speeds at which J-type shocks appear. Due to the
density-dependence of the critical shock speed for this transition, higher
gas-phase SiO fractional abundances are produced behind shocks propagating in
lower density gas. For shock speeds near the threshold speeds for both core and
mantle sputtering, sputtering is much greater for shock velocities at smaller
angles relative to the upstream magnetic field. At higher shock speeds, the
angular variation is still present but less pronounced.
