Ducting Systems and Air Ventilation - Help please - Insulation blocking Return Air Ducts

1960's house. 2 story colonial. Forced air A/C and gas heat.

The basement is half finished (old painted wood paneling, glued on ceiling tiles, newer carpet etc) and half unfinished (mechanicals, storage).

Thus some of what I am telling is not exactly clear to me as I can't see all of the work.

These are the return air ducts:

-Living Room (on slab) at floor connecting to rest of house with basement

-Kitchen (near garage) at floor, with visible paper that implies fiberglass insulation rolls (not blocking duct) but the paper of the insulation is visible in stud space above the duct inside the grill

-Dining Room near Kitchen (middle of house) - this is above the finished part of the basement. Can't see anything in particular here. The Grill is painted on and I would have to cut it to look in.

-Bedroom #1 (seems right above Dining room in center of house) -- can't see anything here, also painted on.

-Bedroom #2 -- at exterior wall, behind grill is some reflective paper, with paint over it, and a couple pink wisps of what looks like fiberglass insulation roll. This probably goes straight down the stud space to the unfinished part of the basement. When I opened a panel in the duct in the basement, I noticed fiberglass rolls insulation occluding the duct going up the stud space. I don't know how much air goes through there, as closer to the furnace, the wide open Living Room vent enters on the way.

-Bedroom #3 -- at exterior wall, same situation as Bedroom 2, with I presume stud space with fiberglass insulation likely behind a taped over duct behind the grill. But this probably goes straight down probably in exterior wall stud space of Dining Room and into finished part of basement and likely in ceiling of basement back to unfinished part of basement at last moment before hitting the furnace.

The furnace has a pleated filter that is supposed to be excellent against allergens. I had a HVAC over to discuss the whole situation and he says that this is common and nothing to worry about.

I have had the ducts "cleaned" twice. Obviously they probably didn't get anything from those occluded ducts, and also probably almost zero from the ducts in the finished part of the basement. (The return air ducts that go through the finished part of the basement tie in to the ones that go through the unfinished part at nearly the last moment before the furnace).

Here are my questions:

Do I need to do anything? Is this a safe situation?

In the unfinished part of the basement,should I seal off the stud space return duct from Bedroom #2, to isolate it? Should I rip open the wall (which is an exterior wall) to get the insulation out? Should I do nothing?

In the finished part of the basement, what do I do? Nothing? Seal off right at where Bedroom 3's occluded air duct enters the unfinished part of the basement, leaving a large area of duct in the ceiling and wall that is isolated and not ventilated? Rip apart the whole basement, removing all the ceiling tiles and wood paneling to clean that duct in the ceiling (which I think is the duct from dining room, Bedroom #2 (interior duct) and also from the stud space Bedroom #3 duct), and isolate the stud space Bedroom #3 duct?

I'm concerned that insulation is in the potential air return space, but the HVAC guy that came over said that that's common, and probably they didn't want all the cold air from the exterior wall entering the system, and that the pleated filter is probably fiberglass also, and not to worry about.

What do you all think?

Thanks

Ideally the return air ducts should be built the same as the supply ducts but the reality is that often the spaces between joists and studs is simply enclosed to use them for return air. If I am correctly interpreting what you wrote I think that you are looking for trouble where it really doesn't exist.

thanks for your response.

my main concerns are that

-some of the ducts appear occluded with insulation roll in the stud space on the exterior of the house

-some of the ducts are not really cleanable

i've had 3 or 4 people say the same as you: "why are you looking for trouble, it's not a problem..."

thanks again for your help

Duct cleaning in residences is mostly a racket. A true duct cleaning will cost several hundred dollars and take most of a day to complete. Anything else is mostly just for the benefit of the contractor.