Stuck alu seatpost in carbon frame

I removed the seatpost. At the outset, I should say it was impossible to remove it through other means given the risk of cracking the carbon frame. However, the method I eventually used to remove the tube was destructive. I will get the frame thoroughly checked before I even consider riding it.

*Method: how I did it

• 
  Here's the tools I used.
  
  

Hammer, narrow short & long screwdriver, metal hacksaw bit & plastic handle and torch.

• I began by cutting off the seatpost one inch above the seat tube. With the torch, I tried to guage how long the postwas stuck in the tube. I made a mark on the blade at the same length as the seatpost so I wouldn't over-cut into the frame accidentally. I then slowly started cutting the first slit through the tube. It took a while to get going, the difficult part is to keep pressure evenly all along the post, top and bottom. It took ages, but after 40 minutes, I had a nice groove going. I would keep checking the depth of the slits with a torch to ensure I didn't start cutting the tube.
  
• I kept going until I thought I was micrometres from cutting through the tube. I then made about four more grooves every 5mm making four strips. The theory was to nearly cut through the tube making it possible to lever them out with a wedge.
  
• After making 5 grooves, I started carefully wedging a narrow, short screwdriver between the seatpost and the seat tube; I gradually hammered the screwdriver into the tube. The first strip broke off and fell into the tube.
  
• I repeated this as the opposite side and the same thing happened.
  
• By that stage, removing the rest of the post was a matter of grabbing it with a pliers and pulling it out with a little force.
  
• On inspection of the remaining seatpost, I could see that the post had completely glued to the tube. Unfortunately there was some damage to the bike, so now I'll have it fully inspected to see if the frame is now usable.
  
  
  
  

Photos of the job are below

Outside seatpost covered in rusty, sticky, mouldy goo.

Left shard was the first removed, the rest followed. Only one half of the tube was cut.

*The needle and the damage done: some striations and very shallow chips on the
seatpost housing and the beginning of lots of rust and goo in the seat tube.

*QUESTION: What's the best way to clean out the gunk from the seat tube?