Dark patches on knees

[LilaGrace]

Can anyone suggest a way to lighten the unsightly dark patches on my knees? Either a lightening cream or other remedy you've tried that has worked?

www.mumsnet.com/Talk/style_and_beauty/2577061-Dark-patches-on-knees

www.livestrong.com/article/89821-rid-dark-spots-knees/

I have found heel repair cream works on my elbows (when I remember to use it)

I'm going to try the lemon juice/exfoliation thing. But ideally I'd like to hear from someone who has used something and seen results- happy to try a natural remedy or a bought cream etc.