How do I clean a stain off the blue stone on my outdoor walkway?

TSP might work. Muriatic acid is another option, but you'll likely end up doing your entire walkway to keep the appearance consistent (it really cleans!). Wear gloves and take care.

First try old faithful, a solution of baking soda and vinegar. Depending on the size of the stain, I suggest you use more baking soda than vinegar and make a paste. Let it sit a moment and then use a brush to scrub it. Hopefully do this once or twice will work.

My second suggestion is to use ammonia by pouring it directly on the stain, and then use a scrub brush.

Lastly borax and vinegar may do the job too. I hope these work. I believe they should.

Try using a sander/sand paper.

Uses Mr. clean magic eraser! Rub well, rinse clean! If you need a little “grit”, sprinkle. Little table salt on it. Dampen the Magic Eraser with just a drop of Dawn dish soap.

Try TSP or Krud Kutter. Muriatic acid is used etch a stone surface before staining or painting. Don't use it.

I would first try Barkeeper's Friend and a stiff scrub brush. Don't use anything acidic as it can etch the stone, ruin the sealant, and/or destroy your grout. If BF doesn't work, try baking soda and vinegar. I don't think 4 days exposure will require anything too drastic.

KrudKutter or Purple Power cleaner degreaser from the auto store.

This happened to me with a new bluestone entrance porch as well. I cleaned it with just bleach and water. I poured 2 cubs of bleach into a 3 gallon bucket while it was sunny and let it sit for about 30 minutes then I hosed it off and the stains were gone and my bluestone was not damaged. The bleach and water solution has become my cleaning solution about every other month to keep it clean.

In regards to the stain on your bluestone, which suggestion did you use and was it a sucess?

Thanks.