Why on earth did you 'mangle it "?
If you attempted to cut it apart or something... thats just foolish.
It has been mentioned here about 300 times that the way you clean a 2 stroke muffler out is by BURNING it out.
No damage... low hassle... works perfectly... (and by the way is recommended in many service manuals)
If you had an oxy-acetylene torch.... that was the correct tool... put on the cutting torch tip (don't pull the oxygen trigger though)... and get the muff up to a glowing red all over... then place the torch in the muff inlet.... the interior will be back to bare metal with the internal holes the size they were the day it came off the assembly line.
(its in the guide)...