what to do with/about sth

[joham]

I don't know what to do with/about it.

I thought in this situation there was no difference between 'with' and 'about'. But one of my net friends didn't agree.

Are they interchangeable?

Could I ask native speakers to help me please? Thank you in advance.

[bhaisahab]

'I don't know what to do with this piece, I have lost the instructions.'
'I don't know what to do about my son's education, he is so difficult.'

For example.

[joham]

Originally Posted by bhaisahab

'I don't know what to do with this piece, I have lost the instructions.'
'I don't know what to do about my son's education, he is so difficult.'
For example.

Thank you for your kindness, bhaisahab. I'm still not very clear about that. 'What to do with sth' sounds like 'how to deal with sth', am I right? And 'what to do about sth' sounds a bit broader in meaning.

Can we use 'with' in the following context to replace 'about'?

Whatever you choose to grow, attention to the soil is critical to success. I always start a new garden with a professional-quality soil test. It tells me if lead and cadmium are present in the soil and what to do about it if they are, what the pH is and how to fix it to bring it into the vicinity of 6.5, and what kind of fertilizer to use, how much, and when.

Thank you again.

[bhaisahab]

No, in that example you can't substitute with for about, you can't do anything with the lead and cadmium in the soil, you can't even see it, you may be able to do something about it however, in other words find a remedy to neutralise its effects.