Pre concaving days, the bats only had 15mm edges etc
I managed to remove 2-3oz by sanding the huge spine and around 3mm off the whole profile ,checking the pick up as I went, of a laver I had.
It doesn't look pretty, but I couldn't use the bat before the sanding, after the weight removal, I won the batting avgs with over 600 league runs, and the bat went on to score a lot of runs, before a cheap ball destroyed the middle on it.
If you can't sell the bat, then removing weight until it feels right is a definite option
A lot depends on what tools you have to hand,(I work for a furniture manufacturer) as to how long it takes to remove the wood.
A bit of concaving is fine, but when you get a profile similar to M&H Compton bat, then to me that's stupid..