cleaning fossil plates

[Scottnokes2015]

Hi everyone,I am in the process of cleaning some plates I collected recently and a couple is layered with this green covering. I removed quite a lot with alcohol and toothbrush. Does anyone have any better way to get it of. I wondered abit bleach but worried it might damage the fossils. Is this green covering harmful.

[Fossil Claw]

Pics would be helpful.

Depends on what the fossil is made of and what the "green" is.

[Ptychodus04]

Pics would be helpful.

Depends on what the fossil is made of and what the "green" is.

Agreed. Pics please.

[Auspex]

If it is algae, a 10% bleach in water solution should clean things right up. Soft brush it, and rinse it well.

[Blastoid]

Try a test with a piece you don't value. Bleach works well and quickly on green algae, it's awesome.