Notated with a verbal instruction, sometimes with a wavy line.
This is normally used as an exaggerated effect on the clarinet.



A slide in pitch between notes. Clarinet: works best between (written) D4 and F6. Avoid in the lower register.
Bass Clarinet: glissandi don't work, because of covered holes. Fast chromatic scales are substituted. Glissandi on the clarinet:
Glissandi on the bass clarinet:
Gershwin's famous glissando in Rhapsody in Blue:



Produced by fingering a fundamental low note, then picking out partials using venting, register keys or octave holes. Notated with a o over the notehead. (It is probably a good idea to include a note explaining whether the notehead is the sounding or fingered pitch). Harmonics are very rare and fairly ineffective on the clarinet.


Tremolo or "Shake"

Tremolos on bass clarinet
A trill between two notes more than a tone apart. These are possible, but avoid crossing the register break, especially on bass clarinet (which sounds particularly effective in the bottom register).
Bass clarinet tremolo:



Trills on clarinets
A rapid alternation between two pitches. The notation above, read in treble clef, shows a minor trill followed by a major trill, indicated by accidentals over the note. If these are not given, players will choose trill type based on musical context. The wavy lines indicating duration of trill are also optional. All trills are possible on the clarinet and on the bass clarinet (except very high on the instrument). Timbral trills involve trilling between alternative fingerings for a given note, or using very little embouchure.
Bass clarinet trills:
Timbral trills on bass clarinet:


A very quiet sound. Notate with a verbal instruction: echo tone, subtone, mezzo voce or sotto voce. An extreme pianissimo will be drowned out by other sounds.