Being a flat faced pooch with lots of skin folds, I tend to suffer from quite bad tear staining. I have tried various things in the past; olive oil, sudocrem, shop bought tear stain removers... But nothing really worked.
Then mum read about Apple Cider Vinegar which supposedly neutralises the reddish colour and makes the tears come out clear. I've been having a teaspoon of it daily in my water bowl for the last two months and my dog, has it made such a difference!!! And I don't even mind the taste!
I highly recommend this. Mum says it's so cheap compared to other methods and very easy to use ;)