Good question. Research indicates that the riskiest way of using meth is to inject it. When injection equipment is shared it is known to spread blood-borne viruses like hep C, hep B and HIV. Using new needles, spoons, water, swabs, filters and tourniquets every time you inject will help reduce the harms of contracting infections. CATIE has published a comprehensive booklet with information on safer injection practices. Finally there are several places across Manitoba where people can access safer drug supplies including sharps disposal containers.
Hope this is helpful