Let's understand the situation
You are using an oil based paint .We know oil contains hydrocarbons means CH- bonded compound . Hydrocarbons are known as organic compounds and non polar .The thing non polar doesn't matter much but thing organic matters .
Now coming to water ,water contains OH bonding ,a lone pair is present over O which makes water polar . Although water is also known as inorganic compound.
We know that like dissolves like .In that manner Organic compounds are soluble in only organic compounds and not in inorganic compounds like water .Thus oil paint is insoluble in water as particles don't dissolve
Hence to clean the oil you need organic solvents like toulenw,spirit ,Benzyl compounds etc .