You said it muddies local history, but I think letting people get excited about rocks is how real interest starts.

Wait, did you try flipping them halfway through? I've had that brand turn out fine when I gave them a good shake at the 8 minute mark. My oven runs a little hot though, maybe that's the difference.

My grandpa's old ziploc bag of water trick works every time.

Seriously? It's just a driveway... not a heart surgery. The old guy probably had too much time on his hands. I get that the tip helped, but people act like these little tricks are life-changing. It's concrete, it's gonna crack anyway.

Got to agree with @felix98. The old inspection mirror never needs a battery. Can get into tight spots a camera just can't. Plus, you're not worried about dropping it.