Sorry FJZR,
I was thinking of axle spacers and not swing arm spacer. Swing arm spacer removes quite easily and bushings can be removed like Fred says or by tapping out with a punch.
On the new side, most use the brass bushings for replacement. But you must clean up the swing arm and check the clearance on the bushing to swing arm and the bushing to swing arm pivot.
Some bushings have been too tight to press or squeeze back into the swing arm and others report pivot bolts that don't fit.
Should be about .001 th interference fit between bushing and swing arm so a little tapping with a brass or ball peen hammer should be all it takes to install. I used a long threaded rod with nuts and washers to pull mine together.
If the axle is tight on the bushing, a little honing is needed to give just a snug fit on the pivot. Meaning a rubber hammer tapping on the end should be the max force to install otherwise it's too tight.
Good Luck.