Here in Bucks its a verb - Biffa means having a thoroughly good clear out. Used and understood throughout the village.
Don't forget that it is a capital 'B' as it originates from the
re-cycling company Biffa but applies to any skip, general tidy up or clear out including packing stuff up to take to the
dump or charity shop. Can Biffa out things like the
car or your pockets. 'Biffared out' is also quite acceptable.