If the distributor is OEM then I would pop it apart and clean the varnish out of it. I used WD40 and a brass tube brush to clean the body and then some 0000 steel wool to clean the distributor shaft. The shaft will have grooves in it so make sure to get those cleaned out as well. Some info in this thread with me babbling about differences between the two that I have:
It appears that some distributors came with two different styles of collars. This is part #12 in this distributor diagram (I know the diagram is for a 94/94 car but you get the idea):
| Item | Part Number | Description |
|---|
| 1 | 388483-S2 | Screw (2 Req'd) |
| 2 | — | Armature (Rotary Vane) (Part of 12127) |
| 3 | — | Shaft Assembly (Part of 12127) |
| 4 | N801293-S36 | Screw |
| 5 | — | Stator (Hall Effect Vane Switch Assembly) (Part of... |
I did not take pictures of the shaft before it was cleaned up but here is one of it clean and one where you can see the grooves I am talking about:
I used a small pick to get most of the crud out of the grooves then I finished them up with a small brass brush and WD40.