I posted these in another thread but they explain how I got the s-type threaded valves out with little to no damage.
https://youtu.be/eJWv_gn9VOQ
https://youtu.be/l63j-ROtyNo
Old post bump... The S-type threaded valves are not too bad to take out. A little practice makes it easier.
https://youtu.be/eJWv_gn9VOQ
https://youtu.be/l63j-ROtyNo
Hopefully these will help anyone looking for a how to on removing these. Good luck .