It is important that you burn dried, suitable fuels in your appliance. Doing so prevents the formulation of creosote, which can clog a chimney, effect the draught needed to draw smoke out of the pot and cause a fire hazard. All fuels create a layer of soot, however, and as a result the flue needs to be cleaned annually to keep it safe and functional.
Part of the service, is a smoke test to make sure that your chimney has the right amount of draw, to pull the smoke up the flue and out of the pot. Smoke from burning fuels produces carbon monoxide, which can be many times stronger than what is emitted by gas appliances. So it is essential to ensure your flue and appliance function properly. You must also have a carbon monoxide alarm near any heating appliance. Check the government web site for more details. https://www.gov.uk/government/publications/carbon-monoxide-properties-incident-management-and-toxicology/carbon-monoxide-general-information
What would a sweep be without his trusty companion? Sweep Dog often travels with me on jobs, especially to elderly customers who cannot have their own pets, keeping them company whilst I clean the chimney. Sadly, I hadn't considered the colour scheme...!