The activated carbon filter, housed in the lid, contains any unpleasant odours for 3-4 months. The lining bags make the task even easier because as well as keeping the inside of the caddy clean, they're biodegradable so you just lift out the bag when full & put the whole thing straight onto the compost heap. The caddy is made from recycled plastic & the bags are based on vegetable starch that will compost within 60 days.