You don't need special 'foliar stuff'; use the micro or veg base from your regular nutes but mixed real weak.

Mixing cuttings is a good way to spread rot from aging cuttings, which can and often DO get a bit of mold late in their rooting time that does not kill them because by then they are a little plant with a functioning immune system.

You MUST sterilize your dome between cycles of cuttings.

Use foaming antibacterial/antifungal bathroom cleaner. Scrubbing Bubbles or the dollar store alternative is the one to get. Spray on a good layer of foam. Allow to sit 10 minutes. Rinse off not too well under the sink sprayer. Don't forget to do the dome too. Using foaming cleanser, you don't have to really get all the bits of dirt off or scrub the trays. It pretty much sterilizes everything, including remnants of dirt.