Saw a homeowner in Springfield try to clean their flue with a garden hose last week.
They thought a quick spray would clear the creosote, but I had to explain how that just makes a dangerous, acidic sludge that can ruin the liner and cause a bigger fire risk later.
My neighbor tried to fix a clogged gutter with a pressure washer. Shot water right up under the roof shingles. Created a massive leak inside his living room wall. The repair bill was insane. Water damage is no joke. Some DIY ideas just make everything worse.
Oh man, I gotta disagree with you a little bit here, @paige86. I've used the same kind of chemical stuff for years without any issues. The trick is reading the label and following it exactly, not just guessing. Your buddy probably didn't wear gloves or left it sitting way too long. Most of those products are pretty safe if you just measure right and don't let it sit overnight. I've cleared some nasty clogs that way without melting anything. Sounds like a user error more than a problem with the product itself.