Radioactive substances can be deadly so it's vitally important to find the right cleaner to clean each different substance. In Space Cleaners, the objective is to clean everything that falls from the sky in the correct order. Use your mouse to cause each different substance drop in to its proper receptacle while avoiding the others that do not match. If the columns have a different type of substance than that of the cleaner below, simply swap cleaners to make sure you get them all. Be careful of the red meltdown meter at the bottom right, because when it feels up - it's game over.