I work on Amals all the time so I have seen this many times.
Depending on how bad it is you can sand out the high spots with 320 wet and dry with a light oil. If its too bad and distorted you wont be able to tune it properly anyway so as the others have said just bin it. Dont bother with Re-sleeve a carb. I used him many times but its now realise its not the best thing to do but before new Amals were being made again, that’s what we all did and had the carbs bored oversize and had SS sleeves fitted. This fixes the sticking for a while but can create other problems. The boring out of the catby makes the flange area weaker and people not in the know over tighten the 2 nuts which distorts the body again when the nuts only need nipping up. Secondly there is no rubber cable boot so water gets into the carby and causes a chemical reaction between the alloy body and the stainless sleeve and this also causes sticking problems again. So I never get Amals sleeved anymore and just fit new ones. The new ones are ok if you adhere to some rules. Don’t over tighten the 2 nuts which distorts the body and fit some sort of rubber boot over the cable or carby top to keep water out. They say the new amals are made from better alloy but they still wont like any moisture. Last of all fit a Mikuni if your not fussed about having a non original carby for the brand of bike you have.