Door Key Cylinder

[Oka]

Two winters ago, the door key cylinder froze. At the moment, my option was heating up the inside of the cylinder to be able to turn the key. I used an old smaller key, from a non exiting car, heat it up and plunged it inside the cylinder. The heat melted the ice. I was able to unlock the door with its (Volvo) key. I later started using the key fob. Much later, I tried to use the key, the cylinder will not turn; till now.

I just removed the key system and the cylinder, which seems to have some crud on the outside. Got them all cleaned up.

If I pull out the guts of the cylinder, will I able to put them back, or is that only for the locksmiths?

Thanks