homogenous means a item/thing which is perfectly mixed. for example lemonade is a homogenous mixture because the sugar, lemon juice and water are perfectly mixed.
heterogenous mixture means a item/thing which is not clearly mixed. for example if you mix sand and water you can still see sand in the bottom of the cup, meaning the sand hasn’t mixed well with water.
plastics and utensils are *considered* homogenous because it has a clean texture and you can’t really tell what has been added to make this from just looking at it.