I'm afraid I regularly get maggots in the outside bin as the cat always leaves scraps of cat food which gets put in the black bag. She also has made a lot of killings this year as, I guess, wildlife is coming closer to the house in search of water, so there's also shrew, mice and, sadly, bird bodies.
Also, my daughter is bringing one rubbish bag a week to put in my outside bin as she only has space for one in her cubby hole with her flat and she has an excess of nappies, breast and sanitary pads (and cat litter) having given birth recently.
Luckily, refuse is collected weekly and a quick swish around with bleach or washing up liquid and water cleans the bin out and the birds can then eat the maggots so it's extra food for them. I'm not squirmish at all so it doesn't bother me. It's all part of the cycle of nature. I compose my own vegetable peelings, tea bags and egg shells as my council doesn't collect food waste,