Help your holding tank work better and keep it from stinking up the boat by tossing in some Free & Clear Holding Tank Liquid Deodorant from Thetford. Free & Clear includes enzymes that break down and liquefy both waste and tissue to prevent clogs. Fragrance- and formaldehyde-free, it is also 100 percent biodegradable to ensure you are taking care of the environment as well. Free & Clear is available in a number of different container sizes or in 12-pack “toss in” form for ease of use. From $10.Thetford Corp.