Pet Store Online Uk

What is the best tear stain remover / treatment for use on a white cat with long hair?
I mean the typical stains of tears – Reddish / brown – that appear around and under the eyes / nose of my white Persian long hair … I looked online and at pet stores and have seen powder (especially for cats show I think) or liquid ….. wondered if anyone had any recommendations – available in the UK, please!
I recommend any of the chemicals, how would you like that chemicals rubbed around their eyes? The warm water and cotton wool is probably as effective (and a fraction of the price!).
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