^^Yes. Since it is bothering you, best to clean it out now yourself. Maybe even clean it every couple of days.

And once you clean it out, stuff in some insulation or somesuch to keep more junk from falling in.

Are you hiring the workers individually? Or did you hire a General Contractor to hire the workers and manage the project? Home Protection through plastic sheeting, zip walls, dust isolation, return vent filtering, etc. is the job responsibility of the GC. Many lower cost contractor do not even include those services in order to maintain lower costs. Check your contract to see if those services were included in your renovation.

we hired a GC but he never seems to be there. and the workers just do whatever with no care at all. I have pulled out bags of lunch, water bottles and such out of the vents.

also I have read to place vent tape over the sides of the vent and where the floor meet to close up any open spaces to not lose air.

Sloppy, don't care contractors and subs are everywhere. It's your job to screen, ask questions, then hire the right one.

Next time, prepare your own scope of work.

We had to replace our gas water heater this week. When I pulled the flue pipe out of the wall (vents into a clay tile flue next to fireplace chimney), I discovered that the pipe elbow was almost half way obstructed with debris from when the chimney was constructed--chunks of concrete & clay tile.

I also learned a lesson in doing periodic inspections of the flue pipe, too. Whoever installed it had the pipe running downhill! The pipe had rusted & corroded. Almost 2/3 of the downhill section was totally eaten away. Probably because condensation had collected there. And age, too, of course. (This portion of the flue was behind a cap and inside the base of the chimney structure, thus hidden away.) We've lived in this house for over 20 years with the original water heater from when we bought the house only now giving out.

After seeing the circumstances of the hidden away part of the flue, I was actually happy that the old water heater had given up the ghost! Also explained why I would often smell something kinda' like gas when I was near the fireplace upstairs. (No one else would claim to smell what I was smelling so I would dismiss it until I smelled it again.)