Without proper cleaning, residual coffee oils can build up on your brewer’s carafe, eventually turning rancid and leading to bitter-tasting coffee. Urnex BioCaf Machine Cleaning Powder is a biodegradable, phosphate-free, non-toxic cleaner formulated to remove coffee stains on glass and stainless steel carafes and rinse easily without leaving behind any odors. Each carton contains three single-use packets of cleaning powder.