I put the cars in the dishwasher the night before and it destroyed the paint finish (these cars are several years old anyway). Of course, the peeling paint just added a certain realism to the whole crash scenario.
Then he picked these champagne bottle candles (which we used for an adult cake many years ago). Nice touch. Notice the dripping gel used to write "Happy Birthday Peter." I've been trying to get rid of that stuff for a long time.