I bought some preloved nappies that are quite badly stained. I have washed them in nappisan and hung them out in the sun but with no luck. I think they have improved slightly, so do I just need more sun (it wasn't that sunny today!), or is there anything else I can try? Perhaps soaking in nappisan or vanish?
No offence, but I'd ditch the napisan, it's nasty stuff and really not recommended for nappies. It can shorten the life of the fabric apparently. Sanitiser really isn't necessary, but if you want to use it, there are kinder brands such as Bio-D and Onelife.
Sun and more sun. I stuck a couple of nappies I came to sell outside yesterday when I realised they had little stains on (stupidly sent them to my exs about 5 months ago and I havent used them since so didnt know!) and they are all but gone (some are completely gone) the more you sit them in the sun the better, even on window ledges if its raining out.