Wood or cattle dung ash is used for cleaning cooking utensils in many parts of India. The statement that is not true for this ash is

it largely consists of metal oxides and silicates because non-metals are removed as gaseous compounds during burning of the wood/dung cakes.

when added to water, it forms alkaline solution with pH around 8 and above, which helps to remove oily substances from the utensils.

several chemical components of ash remain undissolved as solids in water and these solids help in cleaning by providing scrubbing action.

if left moist for a few hours in air, it slowly turns acidic because of oxidative decomposition