These things pictured here are filled with swill or gutter oil. This is the stuff that according to chinese sources, at least 10% of all meals here are cooked with. The process is nothing less than filtering out the cigarette butts, the bottle caps and chopsticks and then re-bottling and selling it. My friends from Sichuan refuse to eat at the restaurants due to fear of this stuff.
Check out the articles here:
http://www.google.com.hk/search?hl=en&q=chinas%20swill%20oil&gbv=2&gs_sm=e&gs_upl=2079l10466l0l10720l47l32l8l0l0l0l220l1431l0.4.4l8l0&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1096&bih=517&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi
http://shanghaiist.com/2011/09/19/photos_swill_oil_factory_in_kunming.php
http://www.chinadaily.com.cn/china/2010-03/18/content_9610919.htm