Yowsa........ I consider myself a professional for the most part and I just did this a few weeks ago. Printed a panel and something stopped it and it double printed a section about 2 inches long. While we were doing the others, I took the panel to the back room and proceeded to just scrape the ink off. It came off swimmingly. No scratch makes, no hazing, no nothing. The piece was about 42" x 72". Took maybe 15 minutes. Then, for Murphy's Law sake, I flipped the piece over and printed the other side. Guess what, you couldn't tell a thing and this was not the first time we ever did this. Sometimes ya get a head strike and too much ink goes down..... samating.
Now, if I hadda do a series of them.... or a 5' x 12', no way, but my own in-house mistake..... why not ?? I think it's more professional to know how to fix a mistake than just discarding it, in some cases.