A flashlight that sits unused for years with a cell inside tends to come back with a problem. A post on r/flashlight shows an Olight Baton with visible corrosion and asks whether a vinegar bath or another method could bring it back, along with a new battery.
Leaking alkaline cells are the usual culprit. Alkaline electrolyte is caustic and creeps into anodizing scratches, switch boots, and threads, where it keeps eating metal long after the cell is removed. Vinegar neutralizes the residue and can lift the crust, which is why it is the standard first move — applied with a cotton swab on a small area, then flushed with distilled water and dried thoroughly before anything goes back in.
The harder problem is the electronics. Corrosion that reaches a driver board or a switch contact usually means component-level damage, and that is beyond what a bath can fix. The typical outcome is a light that powers on but behaves unreliably — flickering modes, a switch that needs two presses, or a driver that drains a cell in a week.
Olight's proprietary cells complicate the repair. The magnetic charging system on many Baton models is designed around Olight's own cell with contacts at both ends, and a standard 18650 will not charge through the tailcap. Running a standard cell is sometimes possible with the light used outside the charger, but the light may refuse to run or may not indicate correctly, and mixing chemistries in a light designed around a specific cell is not a project to undertake casually.
The realistic advice is to inspect before investing. If the tube is corroded but the threads and contacts clean up, a replacement Olight cell can revive the light for a fraction of a new one. If the corrosion has reached the driver or the switch, the money is better spent on a new light — and the lesson is to store cells outside the light, at storage voltage, and check them once a season.