Courtesy of a link at Dark Roasted Blend, I was amused to come across an article titled '6 Incredible Toilets in Space'. I must admit, the mechanics of a No. 1 or a No. 2 in weightlessness hadn't weighed heavily upon my mind (or anything else) . . . but I'm now enlightened! Here's an example.
This, we’re reliably informed, is the toilet that went up with the Soyuz rocket circa 1967.
Thankfully, technology has moved on since the inception of this thing, but even so, it shows that removing waste has been a puzzle for astrophysicists since the dawn of space flight.
There's more at the link. Interesting and quirky reading.