Other advice would be. Strip them down clean and rebuild paying close attention to worn moving parts. such as jet needles, sliders and diaphrams. There are a surprising amount of moving parts in there. and always use a magnifying glass. The damage may be hard to see with the naked eye. My son had a small split in one of his slider diaphram and neither of us saw it until i magnified it. caused all sorts of problems. hope this helps.
