Should I cut off the elastic prior to burying?Updated a year ago

Yes. The elastics have enhanced biodegradable properties that under anaerobic conditions (no oxygen) like landfill, make it easier for bacteria to break it down. This speeds up the biodegradation period to between 3 – 5 years (as opposed to 50 years+ for other elastane products).  The rest of the pant can be buried in active soil (which is soil full of active bugs or microorganisms). The garment will break down into natural elements which aren’t harmful to the environment and go back into the soil.  

If underwear is composted, cut off the waistband and leg elastic and remove the third layer of the gusset (the waterproof film) and discard those to landfill.  Cut the main body of the pant being TENCEL™ and Merino wool into small pieces to mix with your compost.