to decipher, make sense of, or explain the truth behind any statement or explanation which has been blown out of proportion to the extent of being B.S.
When Bob told me all about the hot girls at his birthday party, Jesse had to decrapify the fact that they were Bob's cousins.
To fix, remedy, or resolve a product, service, or situation which has been ruined or taken past the point of good quality and/or service. (In short, to fix the shit that has happened.)
My boss told me that Bob's been fired for screwing up the expense reports big time. Now I have to spend the weekend at home and uncrapulate his mistakes