Make recyclable plastic products. The bulk could be pumped back down old holes after removing the sulphur and other needed components. In any case, don't burn it -- you know, don't do the human thing causing all that excess atmospheric CO2 currently overheating our planet. Stop burning methane, propane, butane, natural gas, gasoline, diesel,.. unless.. Unless! They are produced from surface sources like corn, algae, crap trees, and so forth.. {no longer "fossil" -- see what I did there?}
{eta -- and don't otherwise allow the release of fossil volatile or gaseous products into atmosphere either -- that's the really hard part}
Sulphur is also a product of pyrite, btw. A mineral that could be mined if necessary -- i.e. after weighing the environmental costs and benefits of each available extraction method. Finding ways to use less is always good
