Provided are methods and compositions for inhibiting carbonyl based fouling materials of basic wash systems. Said methods comprise contacting the hydrocarbon stream that is or will be subjected to said wash systems with water soluble or water dispersible copolymers. Said copolymers comprise repeat units of ethylenically unsaturated monomers such as acrylic acid with other repeat units such as alkyl acrylates, allyl ethers, ethoxylated allyl repeat units, etc. In other embodiments, a third repeat unit is present and may comprise a hydrophobic moiety such as a styrene repeat unit.