I spent the morning helping my neighbor pull all the sheet rock,appliances, toys, etc from his garage. He was lucky that when he set it on fire there was no real structural damage, only smoke damage. He did something I've heard warnings about all my life but really didn't believe.
After doing some remodeling in the house he took some rags that were saturated with linseed oil and put them in a plastic bucket with some other debris. He put the bucket in the garage and went to bed. 4 hours later he wakes up to the sound of the smoke alarm. He thought because it was in the 20's that night the rags would be safe until he could properly dispose of them. I've always heard oily rags could start a fire but never really believed it, but it does happen and a lot quicker than you might think.
Luckily his wife and kids were out of town, there would have been some serious panic if they had been around, and there would have been a pickup truck in the garage as well. His homebrew kegerator, 2 kegs and the CO2 bottle are all fine..