You cannot re-use the oil in the can. As for glass particles I don't believe this to be true since steel wool is in fact just long strands of coiled steel. If you purchase a pretty coarse steel wool that will not rust you will be safe. The fine mesh steel wool tends to break apart easily. An alternative that I was thinking about are bio-balls that are used in fish tanks. You can find them in any pet shop. Either way, I plan to run with the steel wool for a few months and see what the results are like. If it's bad, I'll switch to something else to baffle the can.