[olsaltybastard]

Once the stuff begins to die off, you have to expect a certain odor which usually multiplies the longer it is out of water.

I would obtain a rubbermaid container (or two), add the rock and some freshly mixed salt water, throw a powerhead in there, and let it be for a few weeks. The smell can get bad, so it may be better to do this outside. If you live in an area that gets chilly, you can add a heater.

If it's not to bad, you can add the rock to a tank, and cycle it that way. I have found out how bad LR can stink up the inside of a house and I don't want to go through that twice (hence the advice to do this outside.)