We (Snowdog and I) use squeeze marjorine, available in 1 lb bottles. We take 3 for a week or so. We also take 1 1/2 pts of canola oil in a nalgene bottle. All of the bottles are put in ziplocs for safety. Only had one trip where the oil bottle sprung a leak, but cleaning up oil in a foodbox is one picnic I have no desire to repeat. Its also good insurance in case some seasoned veteran doesn't get the top closed tightly. :o