HG chewing gum remover (HG product 97) freezes the trodden in chewing gum, making it hard and brittle. The chewing gum can be easily removed when it is like this.
Put the tube supplied into the valve on the spray can and spray as close as possible to the chewing gum. Remove the chewing gum with the hollow side of a spoon. On shiny floors a plumbers knife can be used, if necessary.