What kind of white stains are on my foamposite's sole (black sole)?

[Ozone11]

Sorry im new to this forum, so i dont really know what r the rules here. I'm having these white stains on my foamposite's sole which happen after I used it while it was raining. It was 2 years ago tho. Do anyone hv any idea about what this is or how to get rid of it? Cause I wanna sell it and I want to know what these white stains r, so I can describe it to the potential buyer that these stains can be removed or not.

 

[aquatic barefoot]

It looks like dried residue of whatever was probably in the rainwater you walked through or stepped in. Should come right off with a rag and some water.

If plain water doesn’t get it out, try some dish soap and brush.

If that doesn’t work, I would just list them as is and share what you already wrote in your original post.

 

[Ozone11]

thanks for the reply. I've washed it with dish soap and brushed it with a toothbrush but the stains r still there. I once read a term called blooming, white stains on rubber hunter boots. I thought there might be a term for white stains on black rubber soles like what I hv here. Once again thanks for the reply. I will list it as it is if there isnt any answer for this problem anytime soon.