I’m thinking washing them off with water will not work, that soot smears really easy. I would try insecticidal soap on a very small portion, and see if that removes the soot easier.

Ah, I’m sorry you had to go through a house fire. It is a long process to come back, but you can do it. :)

Great tip on the isecticidal soap! Thank you so much!

The blue Dawn dish detergent or Dr. Bronners are common and popular products used on plants for insect control, so since you already know they're mild and safe to use on orchids, I'd go with either of those. Personally I'd go with Dawn in this case. I'd hose them down outdoors very well, to clear any residual and possibly toxic debris from the pots, and then spray them with a Dawn/water mix, and then rinse thoroughly again. They will probably recover just fine, if they're rinsed/soaked thoroughly.

Good luck!