To be in the process of either
-To be effortlessly winning at any form of
gambling where one plays against The "house" or "bank". Now extended to also mean effortlessly winning at friendly card games or any form of gambling.
-To be
pulverising the
opposition when heavily outmubered. Can refer to massacres, brawls or anything similar.
"He was cleaning house at
the craps table last night"
"He's cleaning house at the drugs den because he has a wicked
AK."
"
The undertaker is in the ring and is cleaning house."