If its a spot from an iron, its not actually rust, its just dirty water from inside the iron, if it's on the white part dampen a white towel/ tea towel use a little dawn and warm water, place the stained part face down on another white towel or paper towel and dab from the back unti the stain has transferred to the towel underneath. If you do it on the stain you risk pushing the stain further into the fibres. This works with most stains.