If you have Vag Com, you can pull the fuel hose off the hard line and empty the tank via vcds.
Takes a couple minutes to do from start to finish – just make sure the car is cold when you pop the lines as it will spray everywhere.
I drain my pump gas into a couple jerry cans, fill up with race gas, run around the block then switch to the 100 file. Burn up my gas at the track, fill up on premium on my way home, dump the stuff at home back in the tank when you make room.