nail-polish remover = acetone.
other good things are isopropyl alcohol (2-propanol) and ethanol (95%+). i've got access to photometric grade stuff, but the sterile isopropyl you can get at your average drugstore or supermarket is ok too. i like to use q-tips to gently rub the chips too. the q-tip has a little give--if you push too hard, it just bends.