To get the 5th/reverse sleeves "split" (they reduce tension on the bore and) so they can be removed with a pair of pliers, I use a very small__miniature__screwdriver that I've dulled all the corners on. That prevents it from biting into the aluminum bore while trying to get it to roll in on itself.
I have to admit though, some are definitely harder than others to remove, it doesn't always go so easily for me either
1957 Austin-Healey 100/6 Wine Red
1961 McCulloch R1 go-kart Screaming Yellow
1995///M3 Coupe Dakar Yello Eurosport Twinscrew S/C
1999///M Rdstr Cosmos Black Eurosport Twinscrew S/C
2001///M Rdstr Steel Gray
2011 X5 35i Sport Deep Sea Blue/Cinnamon