About Composite Decking Cleaner Our advanced formula Composite Decking Cleaner provides highly effective results for cleaning & reviving plastic decking, sheds, and fences. It cleans and revives decking made from made from composites. The Composite Decking Cleaner can also be applied directly to the surface with no scrubbing required to kill green algae, lichen, and mould. In these instances, simply water the Composite Decking Cleaner over the contaminated areas and leave it to remove the stains! Available in 5 Litres.