I remove it at the end and count how many times it rotates as it unwinds until slack. This gives you a rule of thumb to go by when re-installing. It may need a turn tighter during assembly, but I wouldn't overdo it.

pry the spring at the frame arm so you can use pliers to remove the spring. it should have 4 turns on it. it will slide right out, you remove the switch stack. clean it and clean inside the frame hole to remove all the old hard grease.

Just add to this, be careful with springs under tension. I once released the spring with my fingers. The end of the spring whipped around and punctured my hand. Fair warning, use a hand tool, or wear a leather glove.