It is rare, but now and then I hear from a reader who is frustrated using one of my all-time favorite products: Nok-Out. I love Nok-Out because it eliminates odors, it's non-toxic, fume-free and kills bacteria, too. Awesome stuff. I mostly receive feedback filled with praise and gratitude, but this week I heard from Linda, who is facing a tough smelly situation that requires more toil and patience because of its location,.

DEAR MARY: I have been using Nok-Out (which was recently renamed SNiPER) very successfully for months. Thank you for the recommendation.

However, I have cat urine odor on my sofa and chair that I can't get out. She sprayed on them. (Did you know that a spayed female cat will spray under stress?) I have soaked the stains thoroughly, more than once. Sometimes the stench goes away for a short period of time; other times it smells like a combo of urine and Nok-out for awhile. But the full odor returns. Help! I can't stand it. — Linda

DEAR LINDA: Oh boy, this is bad. The offending odor soaked into the stuffing of those pieces of furniture. Nok-Out has to penetrate successfully to reach every area that was infected. If the cat truly sprayed, is it possible that the spray went in all directions and you might need to expand the area of treatment?

I sent an SOS to Ted Price at Nok-Out asking him what he thinks your best bet is. I certainly know why you're having this problem, but I'm not fully confident in a solution: The following is my correspondence with Ted. — Mary

DEAR TED: Can you take a look at Linda's cat odor problem, which is included in this column, and weigh in on how to use Nok-Out to eliminate this horrible odor once and for all? — Mary

DEAR LINDA: Sure, Mary. I feel your pain, Linda! But don't worry: There is a permanent solution to this problem and I'm sure I can help.

The most important thing you need to now when using Nok-Out is that it is an oxidizer. When it comes into direct contact with the stinky stuff, it oxidizes (changes) the area so it no longer has an odor. The operative phrase here is: Direct contact.

If you find that the Nok-Out didn't work, it usually means that the Nok-Out did not come into contact with all of the smelly stuff.

For example, I bought a used sofa and didn't discover that it had a horrible musty odor untiil I put it into my living room. I sprayed it all over and it smelled better after drying, so I was happy. But a day or two later, that musty smell returned. I sprayed the couch again, with (predictably) the exact same result.

I put my thinking cap on and did a little homework. I learned that musty odors come from a fungus. In that moment I realized that I had sprayed the upholstery but the fungus was probably living deep in the stuffing. I knew I hadn't made contact with the source of the odor.

I brought out my Nok-Out for a third time and sprayed that sofa heavily . The couch soaked it all up like a sponge and took almost a week to dry. But when it did dry, the odor — and the fungus — were gone.

It has been four years and the smell has never returned. The moral of the story is that direct contact with the source is essential for Nok-Out to do its work.

Considering my experience, I encourage you to re-think your application protocol.

I hope I have answered you satisfactorily, but if you still feel like you have unanswered questions, please give me a call toll free at 866-551-1927. I am typically around from 8 a.m. to 5 p.m all week. Central time. I do return missed calls. If you want to buy more Nok-Out, make sure to mention you found me through Mary. If you order online be sure to use the DPL code for 10% off.

Mary invites questions, comments and tips at [email protected], 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. Mary Hunt is the founder of www.DebtProofLiving.com, a personal finance member website and the author of "Debt-Proof Living," released in 2014. To find out more about Mary and read her past columns, please visit the Creators Syndicate Web page at www.creators.com.

Photo credit: Quinn Dombrowski