Tools, especially those used for the gardening, are subject to severe wear and oxidation. Proper maintenance can help us keep them for a long time.
To clean garden tools you can proceed in two ways, either mechanically, using an iron brush or sandpaper, or chemically, by immersing the pieces in an acid solution. We will focus on the second solution, faster and less tiring than sanding, especially when more pieces need to be cleaned. On the market there are ready-to-use or dilute pickling agents, however it is possible to create economic and eco-friendly products yourself. How to do it is very simple, just buy a jar of citric acid and dissolve a few tens of grams in a basin of water. Just use small percentages (from 2 to 10%), if it is not enough then you can add them gradually. Citric acid has excellent solubility and has good pickling properties combined with a mild resistance to reoxidation (the pieces must be immediately rinsed after treatment). A half-kilo jar of citric acid can be enough for many treatments, moreover it is a product, which thanks to its non-toxicity, can be used for other purposes such as the removal of limestone. The photo shows an improvised pickling pan.
The pieces are immersed in a minimum amount of water and kept submerged for at least half an hour. Times can be very long if the water is cold, if the corrosion is too large or if the acidity is too diluted. Every now and then they should be extracted, quickly brushed and immersed. The production of very small gas bubbles indicates that the process is taking place, if instead we do not see anything after a few minutes we need to increase the percentage of acid. Obviously this pickling is aimed above all for tools that have a normal oxidation, if we have strong oxidations resulting from years of use, it is better to sand first or change the type of acid. Another type of acid on the market (already usually prepared in special formulations) is for example phosphoric acid, which however presents considerably greater toxicity and danger than citric acid. Furthermore, the disposal of these strong products represents a problem as they are not biodegradable.
To complete the treatment of work tools, it is always advisable to apply a film of oil or specific products to avoid future reoxidation.