Maybe I've been watching too many too many Twilight Zone re-runs.
In any case, start with a list of unpleasant, un-natural or "ugly" things. Not necessarily revolting, but don't limit yourself either. Bruises, things you might find in the garbage, roadkill, smoke stacks or oil rigs along the beach. Distasteful is the key.
Now write a poem and find something beautiful in what you see. Visually, emotionally, even conceptually. Dig deep if you have to, but find something you might admire in what you've chosen.
Check out Lines Written Upon A Prophylactic Found In A Brixton Gutter over at The Poem.