Item left ouside muddying/looking dirty

[Kegereneku]

An hopefully simple idea.
It would be a visual effect only making item left on specific soil outside 'muddy', as in texture similar to dirt (or blood) is superposed to those items as time pass.

It would be for ambiance, making them harder to see.
But maybe it's not worth the frustration or retrieving that "damned thing you wanted to haul".

Aside that, retrieving the item would instantaneously clean it. No other game mechanic is necessary, this is purely visual.