Reporting and found rot. How to treat?

[Zoomie]

Good morning everyone. I grabbed three Small Phals off of a fire sale table. All three are in moss and so overwatered that I dumped water out.

Doing repots to bark this morning and found a bit of rot/fungus, mold or some other nastiness. It’s localized but I’d like to knock this out right now.

I did a search here but nothing showed up. Can someone tell me what I can use to treat this without risking injury to the orchid?

Thank you in advance.

Let me jump on my laptop and I’ll attach a pic.