Cleaning O2 Sensors

[Honor]

I just replaced three O2 sensors on my 99 LC with 164k miles. The other was replaced at 121k. Since these weren't malfunctioning when I replaced them I thought to keep one of each for spares. I found a website that says to clean these just soak the sensor part, not electrical contacts, in a cup of gasoline overnight, then let dry.

Any objections or other advice on this procedure?

Here's photos of what I pulled out. Pretty sure they're the original sensors. The downstream sensors both say Toyota 89465-43010 Denso 5351, upstream one doesn't but says Assembled in USA 5360 01M14.