We have great success with oil & grease stains and use biodegradable degreasers to assist with stain removal. Whilst it is dependent on the depth of the stain, in most cases a light shadow of the stain could remain.
Yes, we use high pressure hot water cleaning to remove chewing gum – our results are excellent.
High pressure cleaning can remove some paint from surfaces; it is very dependent on the state and nature of the surface and the paint application. On weatherboard surfaces where paint is peeling pressure cleaning may result in further peeling. It is best to have the job inspected for recommendations.