take one of your old rings and and break them in half (as if they'er not) you can use the end of the busted rings as a really cool tool to shave the grooves back into shape. Just try to keep them standing straight in the grooves as your carving out the black goo.
As for a hone you can make one out of a pencil and some light cardboard. Cut the card board into 2" wide strip about 2' long. Tape one end to the pencil and wrap it tight . round and round till you have a drum almost the size of the cylinders bore. Then cut som 80 grit sand paper and tape/wrap that around the drum till it over laps a few times.
Chuck that whole mess into a drill and spinn it in the bore moving in and out in a fast motion. Then you are comfy that your cylinder is all scratchy and uniform shiny well then it will most certainly hold a nice sheen of oil on its wall to help the rings.
Now GO GO Hurry