1 The most popular type of product requires you to abrade the damage away, prior to polishing the surface to a flawless finish. Autoglym claims that its headlight restoration kit contains sufficient product to renovate two headlamps, although we found that you had to be sparing with the sandpaper. Read any instructions carefully, before starting work. 2 This Renault Clio’s lamp has deteriorated from prolonged UV exposure; note the formation of blotchy yellow marks. Thankfully, the damage is restricted to the cover’s exterior surface. Some cheap bulbs lack a suitable UV blocker, resulting in the lamp cover going cloudy on the inside.
► Eventually, sunlight overcomes the UV-protective coating that is applied to plastic lamp covers, causing the plastic to cloud and ugly grey/yellow marks to appear on clear plastic. Apart from looking unsightly, this situation poses a safety issue. In severe cases, it can cause an MOT test failure, due to altered light output on headlamps especially. Fortunately, the damage tends to be superficial but is easier to rectify if caught early. While some imaginative owners have reported success using mildly-abrasive products, from paintwork cutting compound to toothpaste, a variety of inexpensive dedicated kits are available, which can return your lamp covers to as-new condition.
3 You can avoid removing the lamp, by masking the surrounding paintwork – because you can damage it easily while sanding. We recommend that you buy masking tape supplied to professional body shops; the quality and value of tape from some DIY stores can be very low. While the pictured masking paper is ideal, newspaper would suffice as an alternative. 4 Do not think that you can get away with not protecting the paintwork, if repairing the lamp in situ. Ensure that all tape protects the edges thoroughly. Consider applying two layers of tape, one over the other, to double-up protection in case you slip using the drill. 5 If the damage is fairly extensive, you may find that the kit contains insufficient sandpaper. In this case, we removed the main damage first, by using 500-grit wet-and-dry, used dry. The main damage is removed, when the plastic is evenly cloudy, with no remaining blotches. 6 The main consideration with these kits is that you need to be confident using an electric drill, because the kit contains a drill mount, to which Velcro-backed sandpaper discs mount. Starting with the most abrasive paper supplied (ie. the lowest ‘P’ number), and used either wet, or dry, dependent on the instructions, sand until the lamp’s resulting opaqueness is even. 7 The increasing ‘P’ numbers indicate the reduced abrasiveness of the sandpaper. Use them all; do not skip grades to save
