Hi luvfoxtrot and Telemark - I must say my initial reaction was 'spray oil on my shoes??' But then I had a look at the WD-40 website, and among the '2000+ Uses' it gives 'removing lipstick from fabric' and 'removing Kool-aid stains from carpet' - fancy that! So, maybe I shall have a go (I shall practice on some old fabric first). Thanks guys!
