+@lilypond[verbatim,quote,fragment]
+\clef treble { c'2 c' } \break
+\clef bass { c'2 c' } \break
+\clef alto
+ \set Staff.explicitClefVisibility = #end-of-line-invisible
+ { c'2 c' } \break
+ \unset Staff.explicitClefVisibility
+\clef bass { c'2 c' } \break
+@end lilypond
+
+By default, a clef that has previously been printed will not be
+re-printed if the same @code{\clef} command is issued again and
+will be ignored. The command
+@code{\set Staff.forceClef = ##t} changes this behaviour.
+
+@lilypond[verbatim,quote,fragment]
+ \clef treble
+ c'1
+ \clef treble
+ c'1
+ \set Staff.forceClef = ##t
+ c'1
+ \clef treble
+ c'1
+@end lilypond
+
+When there is a manual clef change, the glyph of the changed clef
+will be smaller than normal. This behaviour can be overridden.
+
+@lilypond[verbatim,quote,fragment]
+ \clef "treble"
+ c'1
+ \clef "bass"
+ c'1
+ \clef "treble"
+ c'1
+ \override Staff.Clef.full-size-change = ##t
+ \clef "bass"
+ c'1
+ \clef "treble"
+ c'1
+ \revert Staff.Clef.full-size-change
+ \clef "bass"
+ c'1
+ \clef "treble"
+ c'1
+@end lilypond