LET'S NOT BE SPACESHIPS.
DON'T PACK AN ALIEN.
In order to prevent the introduction of alien microbes, plants and animals to the Antarctic region, many tour and national program operators will have biosecurity systems in place.
The more you can do before you leave for your trip, the more effective these systems are likely to be!
The most frequent method you will encounter once in Antarctica are boot washes. These have small quantities of anti-microbial disinfectant in them, to help stop us accidentally bringing a virus or other type of nasty alien disease into penguin and seal colonies. However, these will only work if your boots are clean of soil - soil lowers the effectiveness of the disinfectant you see.
Scrub first, dunk second!
But, before you leave remember the four steps to an alien free journey:
Brush. Vacuum. Wash. Check.