Guessing what you meant here; if it's wrong, please clarify. Normally this is done after a filtration. The filtrand is rinsed with solvent to wash off any impurities that may be left. It's rinsed with cold solvent to minimize the amount of filtrand that dissolves.
The filtrate is the liquid that is left after you filter something -- the liquid that is now "missing" the solid that was filtered out.For instance, if you are making drip coffee, it is the coffee beverage (the coffee grinds are called the "filtrand"). If you are removing sand from water, it is the water that is pure (again, the removed sand would be the filtrand).