Golden Wetting Aid, 4 oz.. Wetting Aid (formerly Wetting Agent) from Golden is a concentrated additive used to reduce surface tension of the water in acrylic emulsion. It is effective for achieving rich stains on a porous surface. As with OPEN Thinner and Retarder, Wetting Aid contains no binder and should only be used properly diluted per product instructions. Not for use by children. Eye irritant. Inhalation of Spray Mist Harmful. DO NOT SPRAY APPLY.