Board Thread:Questions and Answers/@comment-168.1.24.117-20160828092056/@comment-69.1.27.102-20170729165614

Mars Incinerators constantly (but slowly) burn waste. As the waste gets burned off, you will be able to clear up more and more garbage piles. If it is taking too long, build more incinerators (and power/oxygen supply as needed) to get rid of more waste.