As soon as a nail driven in the wall becomes loose and the plastering begins to break, it can be made solid and firm by the following process: Saturate a bit of wadding with thick dextrin or glue; wrap as much of it around the nail as possible and reinsert the latter in the hole, pressing it home as strongly as possible. Remove the excess of glue or dextrin, wiping it cleanly off with a rag dipped in clean water; then let dry. The nail will then be firmly fastened in place. If the loose plastering be touched with the glue and replaced, it will adhere and remain firm.