Cleaning old rollers and wheels..?

A screwdriver blade if thick.  It would take forever soaking with solvent only.

Mild gunk- alcohol or Naptha (Zippo fluid)and Qtips or a rag.

(Keep alcohol off white rims, plastic, paint. It can stain plastic(whiter) or remove paints. Naptha won't stain most plastics, but will pull some paints)

Sometimes I wire brush with a stainless or brass wheel& dremel. But loose brush wires flying off have ended up in fingers, toes and motors recently, so I'll be avoiding that now.

(Never steel wool or regular steel brush as the magnetism of an engine might easily pick up stray wires while running.

Pretty much what he said ^.

I frequently use a Scotchbrite wheel on my Dremel, does a bang-up job.  For the really thick crud, I scrape it off with a screwdriver first.  For powered wheels, I stick it in the cradle upside down and slowly rotate the wheels under power.

All of the above is good advice.  As for myself, I use a small screwdriver to remove heavy caked-on crud, then alcohol and lots of Q-Tips.  If necessary, I sometimes use a small (non-powered) bronze brush.

I use mineral spirits instead of alcohol.
And a knife blade, such as an Xacto #19 instead of a screwdriver.
Otherwise, I do the  same as what others have posted.

put this on a Dremel and polish the diry away

https://www.cratex.com/Product...-Wheels/Small-Wheels

we use Q74

If rust scale is not pitted, then Scotchbrite Dremel tool will get you a sharp, clean edge at the flange on the wheels almost all the time. Just be patient and persistent. It does broadcast particles of the Scotchbrite and  grime, so I often sit outside and clean wheels while enjoying a cigar. For tough spots I use an orange Scotchbrite  pad and a lot of elbow grease. For deeply pitted rust, there is no simple solution. The metal is gone. As for the rollers, they're easy. Just look mean at them and they clean up right away.

Bit of a pain, but boy, you can really shine of a pile of wheels this way.  Just use a wire wheel on an old corded drill I have.  You could do it on the bench grinder as well.  That would probably be easier.  For the roller, I just hold the wire wheel to the roller on the truck and be careful!.

I use GooGone. I like it and it seems to work well, for me at least. I know that upsets some. In my case, I don't have any rubber traction tires that may disintegrate. 

Tom 

Old pocket knife and elbow grease.

Charlie

I clean the wheels first with exacto knife then acetone and q-tip.

For any rollers i use dremels black circular sanding disk they are very fine grit and smooth out rollers giving nice shine as well.

Goo Gone isn't too a bad product, but Goof Off is extremely harsh. I think it is xylene, a printers favorite solvent for ink removal. (Printers ink, an oily paste, not liquid, very high pigment count... read as "Messy" with a capital M)