[bell-cot]

Throw all their samples back outside, then very carefully sweep the inside of the LEM and throw the broom & dustpan out too?

In theory, they could have been equipped to partially pressurize the cabin with (say) helium - which would allow some sort of vacuum cleaner to work. But that could have added a fair bit of mass (by the LEM's very tight mass budget standards).

[mapt]

This sort of scenario, which was thought too improbable to plan for, even by an organization as psychotically obsessed with astronaut safety as NASA, is exactly why human spaceflight was important for exploration. Because astronauts could improvise a sensible solution and the tech couldn't.

[jonas21]

If you didn't have the humans on board, you wouldn't need to pressurize the cabin with oxygen. Or even have a cabin.

[dotancohen]

Yes, the presence of humans adds additional challenges that we overcome and learn from. The learning is the entire point of these missions.