A method for reducing antimicrobial compound levels in a liquid composition containing at least one antimicrobial compound. The method comprises contacting said liquid composition with a functionalized resin. Antimicrobial compounds that may be removed by this method include isothiazolin-3-ones, e.g., 2-methyl-4-isothiazolin-3-one; 5-chloro-2-methyl-4-isothiazolin-3-one; 2-n-octyl-4-isothiazolin-3-one; 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one; 1,2-benzisothiazolin-3-one and N-alkyl derivatives thereof, especially N-methyl and N-n-butyl; 2,2-dibromo-3-nitrilopropionamide (DBNPA); 2-bromo-2-nitropropanediol (BNPD); dithio-2,2′-bis(benzmethylamide) (DTBMA); hexetidine; chlorphenesin, C1-C4 alkyl-4-hydroxybenzoates (alkyl parabens); 3-iodopropynylbutylcarbamate (IPBC); formaldehyde releasers and mixtures thereof.