The box can be of any size that fits your needs but you will get props from your other freaky box owner friends the more intricate your box looks, how much it speaks to who you are, if it lockable and if it can be hidden in plain sight.
A 'dirty box' will not protect you from shells as a banana would in the games but it is useful. Those making a split-second decision may initially think it is a beneficial 'question mark box' and coax them into driving into it bringing them to a halt.
Being hit by a 'dirty box' is considered the ultimate insult in Mario Karting worldwide.
The 'dirty box' should not be confused with dirty boxing (topless or naked boxing) or an unclean vagina (also known as a dirty box).
"I just can't catch a break. I was slammed with a blue shell, rodded by the lightning and then to compound it all, I GOT DIRTY BOXED"
"When you're out driving and the guy behind you is up your arse, don't you just wish you had a real-life dirty box?"