Question: Clean scale of the inside of a tea kettle.
Options:
Place a mixture of 50 percent vinegar and 50 percent water into the kettle. Switch it on and let it boil.  Cool, the remove the mixture.  Give the inside a wipe with a cloth, rinse and done.
Place a mixture of 90 percent water and 10 percent alcohol into the kettle. Switch it on and let it boil.  Cool, the remove the mixture.  Give the inside a wipe with a cloth, rinse and done.
Answer: Place a mixture of 50 percent vinegar and 50 percent water into the kettle. Switch it on and let it boil.  Cool, the remove the mixture.  Give the inside a wipe with a cloth, rinse and done.