I used to get all het up about 'off of' but I found out that it has a respectable history going back to Samuel Pepys (this one of quite a number):
Monday 26 May 1662
Up by four o’clock in the morning, and fell to the preparing of some accounts for my Lord of Sandwich. By and by, by appointment comes Mr. Moore, and, by what appears to us at present, we found that my Lord is above 7,000l. in debt, and that he hath money coming into him that will clear all, and so we think him clear, but very little money in his purse. So to my Lord’s, and after he was ready, we spent an hour with him, giving him an account thereof; and he having some 6,000l. in his hands, remaining of the King’s, he is resolved to make use of that, and get off of it as well as he can, which I like well of, for else I fear he will scarce get beforehand again a great while.
Or, if you prefer...
Henry VI, Part 2 - Act 2, scene 1
WIFE
Most true, forsooth, and many time and oft
Myself have heard a voice to call him so.
CARDINAL What, art thou lame?
SIMPCOX Ay, God Almighty help me!
SUFFOLK How cam’st thou so?
SIMPCOX A fall off of a tree.
WIFE A plum tree, master.
Captain Charles Johnson's General History (1724):
"Two days afterwards they chased a sloop of 60 tons, and took her two leagues off of Cape Henry;" –