Flatten the one end of a spray can pipe,stick it in the nozzle of a can of contact cleaner.Leave the ignition OFF.Give the small slot down the side of the
starter button and kill switch a generous squirt,then move the starter button and kill switch on and off for about a minuite .Then give it another one to wash out the junk you have cleaned off the contacts.Then leave it for an hour to dry out before you try it.Use a generous piece of cloth below it to keep the spill off the bodywork.