Hi
I’m doing this human sculpt and I made a new layer for all the veins,
then I accidentally put some muscle and asymmetry details on this layer that I would really like to keep on its own layer, or as part of the default layer.
Are there any ways to kind of transfer partial information from one layer to another so that I could isolate some parts of one layer and put them into another?
cheers. 
you use morph targets and the morph brush.
if you want to bake certain parts of a layer into your model or another layer do this.
with the layer(veins etc.) selected, store a morph target, turn off the layer, then use the morph brush to paint the veins back into your model. its all variations on the steps depending on what you want to accomplish.
Oh man, I had no idea morph targets were layer dependent!
Thanks so much!
um i wouldn’t say layer dependent, more like independent, you can use morph targets without layers at all.
Without layers you’re just working on the default layers, no? 
Well, I won’t argue the semantics, I think it’s a cool feature either way.