ok, it works like this.
you have a mixture of solids. all of the chemicals present in your mixture will dissolve in acetone in a diferent ammount. some will dissolve completely, while some practically wont dissolve at all.
if you "wash" your mixture of solids with acetone, you'll end up with two products. on your funnel or similar part of your setup you'll have the unsoluble solids that are left over.
on the acetone colected you'll have all the chemicals that dissolved in acetone.
depending on exactly what you have on your mixture, you can look up the solubilities and calculate wether this is useful for your purpouses, and in that case where should you look for your desired product: on the acetone or on the funnel.