Scrap biochar?

My boys are builders, and experimenters. We have a covered area on the side of the barn we use as a shop. The boys built a wood stove/ heater thing. It's made out of an old metal tank. There's enough ventilation to burn, but it's not really open like a fire pit. My youngest they burn wood scrap from pallets ( heat treated) branches ect.  My youngest had a project in mind and started collecting the charcoal in the bottom before he started a new fire. He has decided he doesn't want it.  It's lots of different kinds of wood. There are nails in it, and now it's in a wheelbarrow sitting in the rain.  

Can I soak it in compost tea and use it?

Will the nails be a problem?  I figured I can use a magnet to get some out, but I'm sure I won't get them all.

Is it to small and burned up to use?

Looks like char to me. A little rough, but who cares. If you've ever seen char left by a forest fire, it's a lot rougher than this.

Given the variable source of the wood, I don't know I would use it on my intensive annual garden areas. I would stir and pull out all the nails possible (tires vacuum up nails with miraculous efficiency!), soak with free nitrogen bearing liquids, and spread on shrub rows and such.

I agree with Douglas. Maybe not optimal for a raised bed, but as long as you inoculate it, it should be fine for your field or orchard. Crushing it would raise your game a bit, but it would work either way.

John S
PDX OR