Don't worry about getting the sleeve out because you will likely never be able to get it out. Cleaning the baffles is more important. I have had the best luck cleaning the baffles with the sonic cleaner but have not tried simple green.
There has also been on Facebook a promotion that you could get an overstock scope and just pay a shipping fee of $7.99 with your credit card. Again just trying to scam your credit card info.
Got mine apart by putting in padded vise very firmly at the threaded end for the rifle and a strap wrench on the outer end. Was concerned about crushing and making out of round but it is fine.