For a while now, when I twist the volume knob on my guitar, its causes this unpleasant crackling... Kind of like brushing a newspaper against your ear... I've taken it to the shop and they've always told me to apply some Deoxit. Its worked a few times but I'm pretty sure it's an electronic issue because it's never completely gone away. Is there anything real specific I should be looking for? I have an S2 Custom 24. Thanks!