Nope never noticed a small at all I have laid it myself make sure good drainage underneath is good and have never noticed a problem nor has anyone commented. You can buy cleaning stuff for it never tried any of them so cannot comment. If we have loose Poo's (rare0 I make sure I clear as best I can and then take a bowl or three of warm water and rinse the area with the water and sometimes a bit of washing powder or washing up liquid.

Thanks Kazz I will tell her as she was a bit worried about it.

Other than that if they are using one spot in particular rinse it then pop a pot or something there stopping them so they use the rest of the garden.