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WD-40 is one of those products that every household really ought to have stashed away somewhere. Despite originally being invented to stop missiles from rusting way back in the early 1950s, there are now over 2,000 established and unique ways in which the product can be used, proving just how ridiculously versatile it can be.
However, while having a can of the stuff stored away in a cupboard or on a shelf somewhere is all well and good, exactly how long can the product sit there before you should throw it away and replace it with a fresh can? The answer isn't immediately straightforward, as the firm itself states that the formula may well be good indefinitely, but it does take into account the mechanical limitations of how it's stored.
The main concern is the valve assembly of the aerosol can itself, and for this reason, the company states that 5 years is a suitable and safe shelf life to assume for the product. There is, however, no need to chuck a can out just because it ages past this point – WD-40 details how the product can most likely continue to work properly well beyond that time frame.
How to store and use WD-40 correctly
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Naturally, the way WD-40 is stored also affects its service life. WD-40 specifically states that spray cans should be stored in an environment that sits somewhere between 39 degrees and 129 degrees Fahrenheit. In temperatures outside of that range, there stands a higher chance of the can itself experiencing pressure loss, and fire risks also increase. It's also wise to discard any dented, bulging, or rusted cans, as dents and bulges can become a pressure hazard, while rust may allow the formula to escape through holes.
In addition to knowing how to store WD-40 effectively, to ensure its service life is maximized, it's also important to use it correctly and avoid wasting it. For instance, it's a common misconception that WD-40 can be used for squeaky engine belts. However, it's actually terrible for this job, and you'd be far better off using belt dressing or simply adjusting or replacing the offending item.
However, WD-40 is great for removing old stickers from car windows, in addition to a whole heap of more generic uses, like lubricating hinges, locks, and door handles. Keeping cans of WD-40 in good shape, clipping the little red straw in place to avoid losing it, and storing cans at the correct temperature will ensure they stay useful for as long as possible. Reading up on effective uses before reaching for the can will help you avoid wasting it, too.