It is a great temptation to start painting without spending time to properly prepare the surface, but this can be a big mistake. Shortcuts on surface preparation can cause even the highest quality paints to fail prematurely. In fact, experts maintain that inadequate surface preparation is the single greatest cause of paint failures. Whether you are doing interior or exterior painting, good surface preparation requires that the surface be as clean as possible and in good repair. Paint performance depends on good paint adhesion, and paint adheres best to surfaces that are clean and sound.
When drilling blind holes in iron or steel, fine metal bits usually fall into the hole. To remove them, you can use a strong magnet and a soft iron or steel rod that is smaller in diameter than the hole. Push the rod to the hole bottom, then press the magnet to its upper end. Keeping the magnet to the rod, pull it out of the hole and brush away the bits of metal. Repeat until all of the metal bits are removed.