I got a doktor power magic eraser from the range today. It removed eight yellow and red streaks which have been ingrained on my bath for two years! I think they were caused by the kids bath toys, like a plastic residue, which hasn't been removed by bleach, cream cleaner, mr muscle, millions of attempts with various products and hours scrubbing. 30 seconds with the eraser and gone! Witchcraft! Just thought I'd share :-)