I have a Bier de Mars thats been souring for a few months. I've used the dregs of Orval, Ommegang Bier de Mars, & Gueze Boon.
It has been in for 3-4 months, and has a slight sourness, and not much going on on the surface.
I also have a Lambic made with Wyeast Lambic blend that has a thick powdery pelcile on top. Would it benefit the first beer to scoop a spoonful off the top of the Lambic and drop it in?