de-yolking early embryos for microscopy

[Megan Roos]

Hello all.
I am doing some microscopy on wholemount in situ stained embryos of 
8-24H development. I am trying to flatten some out to look at a dorsal 
aspect and having great trouble with interfering yolk grains. Other 
than microdissecting each individual yolk grain away (which is what 
I'm doing), does anyone know of a clever way of getting rid of them 
without destroying my specimen in the process?
Many thanks for any ideas.
Marc.