Forgetting HM moves in Pokemon Crystal version?

Question

How can you forget HM moves in Pokemon Crystal Version for Gameboy Color? Where is the HM guy, what city?

Answer 1

I think he is in the city where clair the last gym leader is. If he's not there try the city with the lighthouse(six gym leader city)

Answer 2

Go to Blackthorn city in Johto, there is a house under a large boulder called the move deleters house, talk to him and he will make your pokémon forget moves including HM moves.