Clean your microwave: Put a microwave safe bowl in the microwave, fill it with water, add a dash of vinegar & put it on for 5 minutes. The steam will soften up all the gunk & absorb the smells. Let it sit to let the steam penetrate.
Onions came from Europe and Africa, it went to North America. It intended to grow, plant, and harvest onion plants, it also was used as an ingredient for certain foods. It did not intend to bring thrips or onion maggots.