Hello,

I am trying to open this grease trap. Can anyone tell me what I'm doing wrong?

Video of me prying the lid with a screwdriver (YouTube)

video of me turning the bolt (YouTube)


Context: We shot an indie horror movie in this storefront theater last week, and despite our best efforts to coordinate our crew, it seems that some of our fake blood and goo (ingredients are water, xanthin gum food thickener, and food coloring, the blood/goo is about the consistency of a vinaigrette salad dressing) and maybe some rubber worms (think rubber fishing lures) went down the drain of the slop sink. At the end of the week we noticed water leaking up out of the top of the grease trap box under the sink. We mopped up the puddle and tried to open up the grease trap to clear whatever had clogged it. The bolt doesn't seem to want to turn more than a quarter turn, even after some WD40. I'm not a plumber but the internet leads me to believe that this may be some kind of child lock mechanism that I can't figure out. I tried pulling the bolt up and out of the trap, in several positions, but so far no luck. My plumber friend suggested that maybe it's fused to something on the inside of the box, and I may need to cut the bolt head off with an angle grinder.

I talked to the theater representative and they've never had to open the grease trap since they moved into the building 6 years ago and so aren't sure how to open it.
Any advice on how to open this lid?

Thank you very much,

bart