Wing cap:Earn 10 stars and stand where the sun shines.Edit the camera and stare into the ceiling.WHOOSH!!
Metal cap:Earn entrance to the basment and find a board called "Hazy Maze Cave".Select the sea monster star and try to find it using the left entrance path and dodge the boulders and take the elevator down.Get to the monster and stand on it.Commit a ground slam and get on its head.Find a metal two door and go for it.Go in the door and find the secret portal to the switch.
Invisible cap:Once again, have entrance to the basement and go into the green walled hallways. Find a door that DOESN'T have a high platform.Now swim where the arrows point and you will find two big pillars.Stand on one of them and do a ground slam.Now do the same to the other.TINK.Open the door to the outside and find a open hole.Now jump into it and find the switch.
There you go.