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Given what goes on in a typical dorm throwing it in a mix of OJ and hair bleach would probably be beneficial. I am only half-kidding, citric acid + peroxide makes for a pretty aggressive disinfectant.</p>
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Not to beat a dead horse too much, but if done due to lack of means you have to respect it. Some years ago I used to live with my family (3 persons) in a major US city on $600/month — TOTAL. We bought our mattress used at a Salvation Army store for $60 and slept on it for 5 years. When I finally got a better paying job and it was time for us to move it was kind of embarrassing to even throw the thing away… it was in such poor shape. We left it by the dumpster but someone picked it up within 15 minutes. When means are limited you focus on the important things. A stained mattress can be “fixed” with a set of clean sheets that is washed regularly. And if you try sleeping on the floor for a few weeks in a row you might reconsider the last statement above :D</p>