a process of recovering bht values from the mother liquors of the crystallization of bht obtained by alkylating p - cresol with isobutylene in the presence of a catalyst and crystallizing the bht , comprises thermally cracking the starting mother liquor at a temperature of from 200 ° c to 250 ° c in the presence of an acid catalyst to reform the cresol polymers , steam distilling the cracked mixture to increase the p - cresol content and remove the diisobutylene , realkylating the steam - distilled reaction mixture with additional isobutylene , to produce a crystallizable mixture of bht having a bht concentration of from 80 to 85 % by weight , and recovering the bht by crystallization . the mother liquors remaining after realkylation and crystallization can be admixed with the starting mother liquors and reused in the thermal cracking step of the process .