I feel wounded for you pal.
I don't know anything about saving bud. Mould is bad, dead or alive. I have chucked easily a Kg this month, but then, it is outdoor harvest season. I feel no differently about it indoors though. It counts for nothing
I think if you wash shake, then the mould should float for a moment. Long enough to fill the vessel till its pouring over the top.
Resin sinks. Though that's not the whole picture.
Is it just the main head?
Think bubble bags. The product sinks. So if you dry sift, the product from that might separate in a glass.
I shouldn't really be thinking about this. Mould and it's byproducts are just not wanted. I know ways of making it appear gone, but the least distasteful is the one where you put it in the bin.
I run plants as fast as 42 days, and still they find time to mould if conditions suit. I think you were unlucky with that main head, and wouldn't expect to see more. I would be rushing to get it out though as that space is no longer productive. It could even be counterproductive. We know it's taking hold.
Do you have plants ready to replace it? Onwards and upwards, and all that.