Take Seven Deadly Cocktail Sticks, some sticky tape (not stretchy), a sharp knife, a file, and a 2mm or 3mm drill bit.
0. check that your cocktail sticks fit inside the spring.
1. cut the pointy bits off, and pick a nice smooth one for the centre.
2. bundle together and tape - not too tightly, so the centre one slides.
3. remove the centre one and tidy the ends of the other six.
4. use the drill bit to make a small dimple in the end of the centre one (helps locate it on the hammer).
Removing a spring without damage is not something I've bothered trying to do.
To fit a spring...
1. extend centre and pop a spring on (as in the pic).
2. locate end of centre stick on spring seat on the hammer (use finger to hold spring on stick!).
3. push, and twist (clockwise, iirc). Or just push. Not too hard though. As long as you only go as far as pushing the springs coils up against each other, it will return to it's normal length afterwards. Ideally you want to rotate it so the very end of the spring wire is at the rear of the keywell (or just load the tool with it in that position, if just pushing).
It's mostly successful
Obviously not as good as opening up the 'board, but a lot easier!
