What next? Some DIY websites suggested vinegar and water, ammonia and water, clear dish soap and water on a cloth or a paste of baking soda and vinegar. I tried a spray bottle of vinegar and water and a Rubber Bush I got at a Norwex party. I sprayed lightly, brushed and blotted with paper towel. Neither the Bissel, nor the vinegar entirely removed coffee/dirt drips and the stairs looked dingy as well. I tried making a foam of dish soap and water -- no real improvement.
So I decided to make my own Resolve style Deep Clean Powder. I had bought the Resolve once, but returned it after reading that I had to brush it on with a special applicator. I put some baking soda in a shallow pan, sprayed lightly once or twice with the vinegar spray to make it damp and then sprinkled on and brushed it in with my rubber Norwex brush.
I am still waiting for the stairs to dry so I can vacuum and see the results. I think this will require some further testing. (I have a small set of stairs going to the basement.) But I am hopeful that this will improve the look of the carpet.
A side note about the Norwex Rubber Brush. I LOVE THIS PRODUCT! It's particularly good at removing pet hair from the stairs that the vacuum did not remove. I used it last week to clean out the car. It requires a little elbow grease, but still easier in my opinion than dragging the vacuum outside.
Update: I went back and stain treated the coffee stains that didn't come out with the Bissel spray. I used a solution of a small amount of liquid laundry detergent and water and rubbed it in with a cloth. I rinsed with a small amount of water and blotted dry -- stains are gone!
The homemade Deep Clean powder didn't appear to make much difference. Can you guess which side I treated?
Before....
After...
I treated the right side! Here is what the baking powder looked like after I spritzed lightly with a solution of vinegar and water
Here it is sprinkled on the right side ....
Here it is brushed in ...
I let it dry for an hour and then vacuumed.
I found a recipe online that uses baking soda, corn starch and baking soda which I may try.