walk through the door
The move deleter in Pokemon silver is located in Blackthorn City.
its in blackthorn city behind the gym
in the dark cave near blackthorn city
It is at he way to blackthorn city
you have to beat team rocket in goldenrod city
get the lendary pokemon lugia then you can go to blackthorn city and go from their
you have to get to blackthorn city first
Via the ice path on route 44
the guy who teaches moves to Pokemon is in blackthorn city
You must be referring to BLACK City, as Blackthorn City is exclusive to the Johto region (only found in Pokemon Gold, Silver, Crystal, and Pokemon Heart Gold and Soul Silver). The amount of people in Black City changes each time you link-up on WiFi.
go south of blackthorn city and you'll find him at lvl 27
Retern to the battle frontier after reaching Blackthorn city