Description from the Otter Wax website: 

Concentrated Castile Soap Canvas Cleaner (5oz Bottle)
For gently cleaning both untreated and waxed canvas.

Our concentrated castile soap is the perfect solution for those who have been wondering how to clean their waxed canvas items. Our specially formulated soap is derived from all-natural plant oils, to gently lift away dirt and grime, while not disturbing the waxed canvas. All you’ll need is a soft bristle brush and a bowl of cool water. Pour some of our canvas cleaner directly onto your brush or even the canvas itself and then dip the brush in some water. The result is a great, deep cleaning foam that attacks built up dirt, dust, and grime, while not damaging your waxed item.

We recommend using this product with our Heavy Duty Fabric Wax, which is a great way to add an additional layer of protection to any of your canvas items, and also a great way to re-proof any previously waxed items.