But the ammonia odor was so strong that he often ... remove the dirt from the spaces between the tiles. They clean inside toilet bowls, using hand mirrors to check their work.

"If you have a septic system, double-check that your toilet bowl cleaner is labeled septic-safe," Christensen says. "In ...

It can also react with other cleaning solutions, particularly acid-based products like limescale removers and vinegar, which risks creating toxic gas. It can even react with the ammonia found in urine ...