Q: We had a kerosene heater malfunction in our greenhouse. Soot covers the plants. What is the safest way to clean them?
A: I’d use soap (not a detergent) on your plant leaves. Soaps include Ivory bar soap and castille soap. Grate some into a bucket of warm water and stir it up. Put cotton socks on both hands and wipe the soot off your plant leaves. Sensitive plants may drop leaves but I expect they will put out new foliage if they were healthy to begin with.