We've (partners) both got Hep C so there is no further risk to us: There are at least six genotypes, or strains, of hepatitis C, which means that you could still infect your partner with a different strain.

Cigarette filters are harmless to use as a filter: Safe filtering has to take account of the way in which filters are used, as well as their properties and materials. The Australian Drug Foundation (the ADF) and VIVAIDS have produced a useful guide to filtering for illicit drug use, which is available from the ADF website at http://druginfo.adf.org.au