After most of the metal has dissolved, the fizzing around each piece should stop.
There may still be some undissolved solids present, such as paint and varnish particles.
Turn the hot plate off and gravity filter the hot solution through filter paper in a funnel
(see TECH Section I.G.). Rest the funnel in a wooden funnel holder. Collect the filtrate
in a 250 mL beaker and cool to room temperature.