A 5-year-employee of the chain took to Reddit.com last year to give some candid answers. We've picked out the highlights below.
When asked about the most disgusting experience in the chain:
Every few months, the restaurant undergoes an inspection from a McOpCo consultant. This is called an FOR. Before the FOR, the owner gets everyone to clean, paint,, brush up on their skills/habits, etc. On one of these occasions, I was tasked with cleaning behind the vats and the grills. The accumulation of grease, dropped, rotting meat and chicken products that were festering underneath was enough to give me nightmares. The grease was pooled on the floor and there were grease stalagmites on the ground. Trapped in the burnt and encrusted filth were hundreds of flies.