Remove Sticker Residue from Plastic Casing

Today I was doing some idle tidying up and I decided I wanted to clean off the top of my Mac Mini. Months ago I had stuck a post-it note to it and the residue from the adhesive didn’t want to come off. I tried wiping it down with a general purpose cleaner, picking at it for a while but it just wasn’t coming off. I don’t know where it came from but I remembered something about using a normal white pencil eraser to clean off plastic. Well I tracked down a white eraser and just started rubbing at it like it was a pencil mark and sure enough within seconds all the glue residue was gone. This should work for any type of hard plastic like an old MacBook or fith or older generation iPod.