Cleaning the rosin off strings can make a striking difference to the sound. A common wine cork serves admirably, quietly scrubbing off the crust of rosin without damaging the winding of the string. A dry microfiber cloth is often recommended; it retains the dust well, but makes a penetrating squeaking noise. A cloth with a little rubbing alcohol is effective, if care is taken to protect the top of the violin from the slightest chance of stray droplets of alcohol touching the varnish. The use of alcohol is generally avoided, as it easily damages varnish in ways which may be difficult or impossible to restore.