વપરાતી કુંચી હંમેશાં ઊજળી રહે.

vaparātī kuṁcī haṁmēśāṁ ūjaḷī rahē.

Literally: A used key always remains bright.
What it means: Skills and knowledge stay sharp only when they are regularly put to use.
The English proverb Shah set beside it: Used keys are always bright.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1921) · read from the scan by machine — the Gujarati itself is unchecked · English is machine-made and nobody has checked it yet

Heard it differently, or know we've got the sense wrong? Tell us — that is exactly the kind of correction this needs.