Easily dirty/muddy feet when wearing flip flops?

[WaitrosePigeon]

Is this normal? How can I stop it? The soles and heels of my feet look so dirty and muddy by the end of the day. Is this normal? I’ve got a lovely pair of Havianna sandals and they are pretty but I can’t wear them! The mud/dirt collects around the straps...

These are the sandals..

Funny I've just put my Havs in a bucket with flash bathroom spray in. Soak overnight. Mine get like that too.

Oh and I wash my feet every night too after wearing them. I've wondered if there's a design fault with Havs as my fitflops aren't so bad.