I have an un-drilled tank, so I use a HOB overflow box. There is a black, pre-filter sponge in this box that requires frequent rinsing due to the accumulation of uneaten food bits, fish poop, etc.
I just rinse it thoroughly under tap water, and then soak it in a bowl of RO/DI water real quick. You could probably even skip the RO/DI soak, but it makes me feel a little better. :bigeyes: