When making my classic terrerium today, I used several old half-used bags of peat to make my peat/sand mix. The bags of peat had been open for long time and the peat itself was compacted into chunks. It loosened up when I mixed it with wet sand, though. I also noticed that it had a sour smell to it ike the way peat usually smells, but stronger. Is it okayto use peat that has been sitting around for several years? It has been kept dry, but looked "stale". Should I remove the plants in my terrerium?