| Clue | Source | Date |
|---|---|---|
| Brush up on a fading skill, perhaps | LA Times Daily | 16 Dec 2022 |
| Sharpen anew | New York Times | 09 May 2015 |
| Sharpen anew | ||
| Whet again | ||
| Whet again | ||
| Make even sharper | ||
| Make even sharper | ||
| Improve an edge | ||
| Sharpen again | ||
| Sharpen again | ||
| Make even sharper |