Recycling trash cans double before my eyes

Thanks for the additional information. Not sure that I can help directly with the count showing double the amount of trash and recyclables as exist ; it may be a bug, or it may be related to the regional sharing of trucks and centers. I have never had this issue, but I've found posts about it back somewhere before patch 2. it's possible if it's a bug it still exists, or maybe existed in an older city that you reclaimed. 

You can't collect from abandoned buildings, so there may be some extra from that issue once in while. I've read that when you demolish your buildings, the bin count doesn't always decrease, but when you add new buildings it always goes up. This means as you rebuild your city you're adding to the can count instead of replacing existing cans as it should. Maybe you gained these "phantom" trash cans when you made space to plop your megatower.  If this is the problem, then it may resolve itself after a few in-game months.

There's a multitude of issues with regional sharing of recycling and trash services. The count in your city might be including the shared city's counts, and the trucks may not be returning to their garages, or the other city has issues that is preventing you from clearing the numbers correctly. 

Recycling Centers:

1. Stop sharing all trash and recycling trucks between the two cities. Just for good measure, after stopping the sharing, demolish all the trucks in the recycling center and rebuild them.

2. Demolish those freight warehouses in your trade depots. They just take up space and steal freight from your commercial buildings. (The only reason you might need them would be if your industry complains that they have nowhere to ship freight.) 

Education:

1. You don't need more than one level of education. Get rid of the libraries, grade schools & all the bus stops. Pick either community college or university.

2. Community colleges and universities have classes more than one time a day, so you can have a larger attendance than capacity. 

3. Remember that residential education comes from students; industrial education (tech level) travels over roads. You'll want your processor factories to be within range of a facility to maintain the tech level to run.,

4. Something that works for me is to use community colleges, and plop more than one rather than adding extensions when needed. The footprint is smaller and you can get them close enough to residential areas so that the students will walk to school rather than drive.

5. You will lose students to the region eventually. Highly encourage you to watch the video I previously posted.

I hope some of this helps.

I wanted to let you know I just experienced this problem for the first time. I've had phantom prisoners in my city for a long time, but never phantom trash. (I got the phantom prisoners because I closed a police station and demolished it with a bunch of prisoners inside, and the game never deleted them. So it says I have 22 prisoners and something like 45 at large, but the overlay shows 2 in the stations and 1 at large).

Anyway, I didn't find a way to solve the problem, but I did figure out why it happened. I usually demolish and rebuild areas during the (Sim) evening or overnight, but this time I was re-configuring a large area and didn't pay attention to the time of day. In this case, I was demolishing about a third of my city and rebuilding it. I paused the game somewhere near the beginning of the garbage collection cycle and demolished a large chunk of residential. After putting in my new roads and zoning new residential, I let it run and build up. The next day it showed double the amount of trash that I actually had. 

Since I play offline, I always save under a different name before I make a big change, so I was able to try it again. When I waited until all the garbage was picked up and the dump was waiting for the next collection cycle, I was able to demolish the whole area without causing an issue with the trash numbers. I did have the same thing happen when my trash dump closed through a whole cycle due to "not enough workers". So, I doubt that it will ever resolve once it's happened, but you can prevent it from happening in the future by letting the garbage trucks pick up all the trash before making any large changes the city.

The only positive is that other than annoying messages and Sims protesting at city hall, it doesn't affect the gameplay. It definitely affects my ocd tendencies, though. Makes me crazy when the numbers don't match.