19. Installation – cleaning the chimney & inspecting the chimney head. Before installing a liner, the chimney must be thoroughly cleaned throughout its length. Be warned that if you fail to get the chimney clean before lining it you run some risk of having a chimney fire in the void at the back of the liner – a risk that's not worth taking. If there are heavy deposits of tar and creosote in the chimney, cleaning may involve some pre-treatment – for details of the recommended procedures click here. XXNext, inspect the head of the chimney to determine how you are going to suspend the liner. The recommended arrangement is to use a plate and clamp (A.) The plate lies flat on the cope and the two clamp halves are bolted together so that they grip the liner tightly and rest on the plate (B.) XXYou may need to trim the corners of the plate with a pair of tin snips to allow the chimney pot to be re-seated back onto the cope.