How about acides? like HCl, HNO3 or H2SO4? or very diluted HF?

Thanks Babak Nasr, I will have to check that

CuO (Cu(II) oxide) can be dissolved in dilute HCl, HNO3, H2SO4, but also in concentrated Alkali.,

Thanks Bernhard Wessling, but can you guide further about which alkali will be suitable for that. How about NaOH

yes, NaOH or KOH (concentrated, maybe also hot) should be ok

Concentrated ammonia should work nicely.

I know that Cu2O dissolves well in concentrated ammonia, not sure about CuO though but you can give it a try

Can copper oxide dissolve in nutrient solution such as Steinberg medium?