How long to soak rocks?

[cichlidcichlid]

I got some lava rock from my neighbors front lawn and i was wondering how long do i soak it to get all the dirt, etc to come out?

 

[Star_Rider]

I boiled my lava rock

 

[desertgoldhound]

Boil and cycle. This will help make sure there are no chemicals in the rock. Always cycle your unknown rocks.

 

[Omega]

I got some lava rock from my neighbors front lawn and i was wondering how long do i soak it to get all the dirt, etc to come out?

If you got it from a lawn, I'm wondering if there's chemicals maybe on them. I'd think if there weren't any chemicals used, spray-washing and boiling them should be fine.