High concentration hydrogen peroxide is insanely dangerous, and where I live doing this would be illegal, so I really don't recommend it.
But from previous research it sounds really simple to concentrate (up to 70%) if you can acquire enough low concentration hydrogen peroxide. So much so that it kinda scares me that I have a bottle of 3% hydrogen peroxide in my house.
Edit: Again, this is a bad idea, but here's the title of my source: Methods for Concentration of Hydrogen Peroxide To Obtain It in Anhydrous Form
But from previous research it sounds really simple to concentrate (up to 70%) if you can acquire enough low concentration hydrogen peroxide. So much so that it kinda scares me that I have a bottle of 3% hydrogen peroxide in my house.
Edit: Again, this is a bad idea, but here's the title of my source: Methods for Concentration of Hydrogen Peroxide To Obtain It in Anhydrous Form