US Patent 4,811,745 assigned to Hercules Inc. Method for controlling delivery of by-products found in cigarette smoke by utilizing a cigarette filter element comprising one or more substrates treated with an effective amount of at least one of (a) zinc chloride, ferrous bromide, calcium bromide, zinc thiocyanate, sarcosine hydrochloride and manganese sulfate; alone or combined with (b) glyceryl triacetate; plus corresponding filter element(s).