If you are desperate you could even use lanolin, but you may have to scrub it off the nappies.
Ali, I wouldn't use even the tiniest smear of lanolin without a liner, unless you want to lanolise your nappies! Lanolin is one of the hardest, most PITA things to get out of fabric, because it is soooo waterproof, and because it will coat the individual fibres so well, even scrubbing doesn't work well. Sure, it's one of the best barrier agents you can use (sunspirit do an excellent calendula infusion in lanolin base, it's fabbo), but I only use it with disposable liners because it's so darned difficult to get off.