Simply pop the small jar into the cistern where forever flush toilet block will continue to work effectively for up to 2000 flushes helping to prevent stains and limescale the coloured water indicates the toilet bowl is sanitary stain free and deodorised up to 4000 flushes in this twin pack non toxic biodegradable safe for septic tanks cleanses and sanitises how to use 1 start with a clean toilet bowl flush the toilet place the jar inside the cistern 2 please allow up to 7 days for