A method of extending the lifespan of a metal cavity glass bottle mould, includes the steps of machining the entire moulding surface of the mould to remove a surface layer of metal, cladding the machined moulding surface by depositing a layer of filler metal onto the surface in a laser cladding process and machining an exposed surface of the cladding layer so as to remove excess filler metal and return the moulding cavity to its design dimensions. The method includes a method of repairing a metal cavity mould by removing surface defects in the moulding surface of a damaged mould by machining the moulding surface and thereafter cladding the moulding surface. The method extends to the cladding of the moulding surface of an undamaged metal cavity mould.