Exiting from lisp debugger?



For some reason, something I did forced me into the lisp debugger, and now I
can't get out of it: my terminal is full of lines like

Break 5 [27]>

and helpful commands (like :top, :R1) which don't in fact seem to have any
effect at all, except for driving me deeper into the debugger.  And even
Ctrl-C doesn't work.  How do I get out of this loop and back to the Maxima
prompt?  I'm using clisp.  What I've done in the past is use Ctrl-Z to exit
to the shell, and then kill the maxima session with kill -9.  But surely
there's a better way.

Thanks,
Alasdair