The most important thing to remember is to get no oil or silicon on the tuning(wrest) pins, the pins are held in position in the wrest plank by friction. Oil and silicon both can reduce friction, the peg cannot then hold the string under tension and the instrument becomes useless. Even if the pins show some rust, which they shouldn’t do not apply either of these substances. It is possible that the strings will show some rust over time. They can be rubbed with grade 0000 wire wool. The same advice applies to the pins. Dust is best removed from under the strings by brushing with a long bristled brush, this will loosen the dust which can then be blown away. I have known people to use a thin item like a ruler with a duster thinly covering it to wipe beneath the strings.
CHANGING A STRING
If you want strings replaced, but don’t want to do it yourself, contact your local piano dealer. They will have the skills.
DOING IT YOURSELF
Strings require changing only very infrequently. If you want to do it yourself you must first obtain the correct gauge of music wire. Supply a sample of the required string to your local piano repairer. They are most likely to be able to oblige, or alternatively they can be obtained from me. When the correct gauge of string is obtained proceed as follows. Study the instrument carefully to determine the string path. Follow the path from where it starts on the topmost of the pair of wrest pins, left, over and under the bridge’s (or visa versa) round the fixed pin, back under, and or over the bridge’s to the bottom of the pair of wrest pins. Only when you are confident should you go ahead. Remove all traces of the old strings. You may find it best to use some small long nose pliers for the task. You will also need a small pair of side cutting snippers. Undo the wrest (tuning) pins about half a turn. Using this method creates least wear in the hole, meaning the pins stay tight, longer. Make sure that the new wire is long enough to pass from the fixed pins on the left to the wrest pins on the right, twice, plus about an extra 150 to 175 mm (6 to 7 inches) each end. Put the two ends together and then overlap the top one by about 25 mm (1 inch). This will allow you to determine the centre point. This is the point where the string passes round the fixed pin, this is where I start. Hold the string in your left hand between your thumb and forefinger at the point where it goes around the pin, and against the pin. Holding the string firmly in your left hand wind the string tightly around the pin using your right hand. You will need to wind one complete turn, and a bit. If you let go carefully now, the string should release to be fairly tightly around the pin with the two ends going roughly in the right direction. Thread the strings over and under the appropriate bridges. Pull the string loosely taut. I then use my left hand to hold the string against the pin while wrapping the string clockwise from the top 4 times before going through the hole and being pulled tightly through with the side cutters. I then cut off the excess leaving about 5 mm protruding from the pin which I then push down with the side cutters. Repeat for the other end of wire. When the string is tightened in the normal manner make sure that the the coil of wire round the pin is not at the very bottom otherwise it will foul the hole. That could result in a broken wire or stripping the delicate thread in the instrument. The wire will bed-in (continue to stretch) for a couple of days.