clear(1) doesn't wipe the scrollback at all, it is still reachable, all of it.
It does for me on the console. The man page says:
# clear clears your screen if this is possible, including its scrollback
# buffer (if the extended "E3" capability is defined). clear looks in the
# environment for the terminal type and then in the terminfo database to
# determine how to clear the screen.
Because of its reliance on terminfo, you need to have TERM=linux in your environment; also, screen/tmux obviously breaks this.