Are your solar patio lights dull and listless? Do they not stay lit as long or as bright as they used to?
Look at that. It’s the solar panel, badly occluded by pollutants and grunge. You can make it look like this again:
And you’ve got the solution already. It’s toothpaste.
Take a small dab of toothpaste, known to the cognoscenti as an all-purpose mild abrasive. Smear it on the sensor and rub gently for about a minute. You’ll feel the grit and, as you work, the sensor smoothing out. Rinse with tap water.
I’ve already noticed my lights are brighter.