Wiktionary
clean out
vb. 1 (context transitive English) To clean, especially to tidy by removing the contents. 2 (context transitive idiomatic English) To empty completely; to remove all money or possessions from.
WordNet
clean out
v. empty completely; "We cleaned out all the drawers" [syn: clear out]
force out; "The new boss cleaned out the lazy workers"
deprive completely of money or goods; "The robbers cleaned us out in a couple of hours"