FES, The hammer and sear pivot pins both have a small "head" much like a nail. The heads are on the left side of a 1911 so the pins are pushed out from right to left when holding the pistol like you were shooting it. To remove the mainspring pin, locate the end with a dimple (lower rear of grip frame) and drive it out with a punch. Inside the mainspring housing, you will find another pin with a "nail head" that prevents the mainspring follower from launching. You have to apply downward pressure on the mainspring follower then push the pin out from the top outside of the housing.
The thumb safety is also the pivot pin for the grip safety. To remove it, locate the thumb safety halfway between SAFE and FIRE. Wiggle it a little and find the sweet spot where the safety can be lifted straight up.
All three "nail head" pins can be pushed out easily. Driving them with a hammer and punch will likely ruin them.