From what I understand:
1- the bliss is steel and doesn't oxidize like the others. You can wipe them with alcohol it won't hurt.
2- The black wheels that are on the bliss, do not use alcohol on. It will dry them out. I use a brush and q tip to clean them.
3- Yes, clean the edge of the carriage with left over batting with alcohol. You will see black come off onto your batting. I roll the machine all the way forward and clean, then back and wipe.
Hope this helps and if not right others please chime in so I can learn.