A discussion on when to compensate for leather losses, how to differentiate infills from the original, and the harmony of infill original. Either liquid/paste or solid fabric techniques can be chosen, depending on the object. Possible materials for use include wax, synthetic resins, leather pastes composed of a binder and a fibre filler. The traditional method is a skived leather insert. When surface grain is very important to the look of an item, photographic inserts can be used, attached to a skived leather insert. The treatment of various items is described, among them a leather-topped desk subsequently protected with an acrylic sheet. In the discussion, mention is made of a scratch-proof, uv-absorbing plexiglas which can be used for such purposes. The possibility of using reconstituted collagen as an infill is discussed. The value of water in solvent mixtures for cleaning leather is mentioned.