| Clue | Source | Date |
|---|---|---|
| Motor oil additives | USA Today Quick | 08 Apr 2026 |
| Line of additives | New York Times | 09 Jan 2016 |
| Line of additives | ||
| Some auto maintenance store products | ||
| Some auto maintenance store products | ||
| Some race-car decals | ||
| Motor oil additives | ||
| P.O. commemoratives | ||
| Organ knobs: Abbr. | ||
| Postage items: Abbr. | ||
| Postal items: Abbr. | ||
| Motor oil additives |