When purifying from pre-seminal fluid, is wiping over socks permissible?

The madhiy (pre-seminal fluid) is impure and nullifies ablution (wudu') by the consensus of scholars. To purify from madhiy, one must wash the penis and testicles, then perform ablution. If a person puts on his khuffs (leather socks) while in a state of purity, he is permitted to wipe over them when performing ablution due to madhiy, because it is among the minor impurities that nullify ablution but do not necessitate a ghusl (ritual bath).