Q: How can you remove the ring around the water line in the toilet? I have tried everything on the market, and nothing removes this ring. I have well water. I have tried many of your suggestions, but do you have any others?

A: Toilet bowl rings are the result of hard water and mineral deposits that develop from the toilet not being flushed multiple times during the day. No amount of scrubbing, harsh chemical cleaners or bleach will completely remove a serious buildup like yours, especially when it’s the result of very hard well water. The solution to that ring along with any other stubborn stains is using a pumice stone — the same thing you might use for callused heals. It won’t scratch or damage the toilet. Any pumice stone will work, but I prefer one with a handle like Pumie Toilet Bowl Ring Remover, which is designed specifically for this problem.

Q: You recently had a short message for college students in your column. In it, you mentioned how kids could get take out federal student loans with no co-signer. Our issue (and some might find fault in us as parents) is that we don’t want to co-sign for our daughter. I believe that in our state she has to be 18 to sign for a loan, and she will still be 17 upon entering college this fall. Where did you find federal loans that could be applied for without a co-signer?

A: You are referring to a legal argument known as “defense of infancy” that says the signing of a contract by a minor does not create a binding obligation. This was eliminated by the Higher Education Amendments of 1992. Your 17-year-old daughter will have the legal capacity to obligate herself to the terms and conditions of a federal student loan on her signature alone. By the same token, she could never use the defense of infancy argument against collection of a student loan.

Thanks for writing and being such a loyal reader. It means the world to me!

Q: My husband and I keep receiving requests from the U.S. Census Bureau to schedule an interview to discuss our household expenditures. This survey is supposedly voluntary. Have you ever heard of this? We don’t want to participate; we feel it’s an invasion of privacy. We trust your advice and perspective. What do you think?

A: The U.S. Census Bureau does use surveys as a method of collecting and analyzing social, economic and geographic data to provide information about the conditions of the United States, states and counties. But unlike the census it takes every 10 years, in which citizens are required by law to participate, these surveys are completely voluntary.

You are wise to be suspicious and concerned about your privacy. The Census Bureau warns folks on its website about scam artists posing as bureau officials. If you do not want to participate in a survey, opt out. You have every right to do that. If you suspect this is a scam artist after your information or you want to verify that whomever is contacting you is legitimate, contact the U.S. Census Bureau directly.

Mary invites questions, comments and tips at mary@everydaycheapskate.com, or c/o Everyday Cheapskate, 12340 Seal Beach Blvd., Suite B-416, Seal Beach, CA 90740. This column will answer questions of general interest, but letters cannot be answered individually.