Hans Grohe Retroaktiv 06126XX0 Installation Instructions / Warranty page 5

If scale deposits are noticed on the spray face, pour
about 3/" of a commercial scale remover, such as
Lime-Away or CLR ,into a shallow dish. Dilute the
TM TM
remover according to the label instructions.
Soak only the spray face in the solution for the amount
of time specified on the label.
Rinse the showerhead/handshower with clear water.
Reinstall the showerhead/handshower. Turn on the
water and allow it to flush for at least one minute.
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