Adding machine repair

I have a pair of Olivetti Underwood 288s (10-key 7 digit input, 8 digit output adding machines), one of which I got from list member Patrick Finnegan a couple of years ago, and one which I found in a local thrift store this summer. Finding the second one inspired me to try to get them working... and I am rather out of my depth. The only electrical part (the AC induction motor that powers the mechanism) works fine in both, but both have other, mechanical issues. I've run them some under electrical power and spent a lot more time slowly turning the mechanism by hand, trying to work out what it's doing. Both have 'sticky digits', i.e. the mechanism that both rotates the type wheels into the correct position during the print part of the cycle and then is added to the accumulator in the accumulate part of the cycle doesn't move freely and thus doesn't print and doesn't accumulate the correct totals. One also has sticky pins in the input register and the other doesn't seem to carry at all and has a sticky 'leading zero suppression' mechanism. First and foremost, the oil in both machines has congealed into a sticky mess. I clearly need to replace it, but I have no idea what to replace it with. I suspect that it's something similar to what's used to lube typewriters, given that they were built by typewriter companies using typewriter-inspired mechanisms? Second, I have no idea how to take them apart correctly. I've successfully gotten the covers off, but I can't even get the ribbon holder/winding assembly off since it's linked to a mechanism that's supposed to lift it to switch from black to red ink, and I can't find a way to safely disengage them... I've also tried to remove the platen cylinder, but the ribbon holder is in the way of the retaining screws. The only other things I can obviously remove at this point are return springs that hold various levers/cams in place, but I can't see how that would help me remove anything behind them, and all of the cams seem to be maually aligned on their axles, held in the correct position by the same screws that would need to be removed to take the axles out. Ease of service does not seem to have been a design goal in these machines :-/ My inability to disassemble them is doubly problematic since parts of the mechanism are buried behind so much other stuff that I can't see what they're doing, and there are parts that I can't seem to get to move using any combination of front panel inputs... there's one bit that I've found a way to reset (subtracting) but not a way to set using normal inputs... and I don't see any way of actuating the ink-color-swithcing mechanism. Does anyone have experience with anything similar that would be able to offer advice? I'd be glad to make photos and my reverse-engineering notes available... They are fascinating machines (the whole accumulator rotates around backwards to subtract!), but I am afraid of damaging them with my clumsy attempts at repair. Since I have two, I guess I can muddle along by trial and error, but I would really love to hear from someone that's worked on a similar device before. Alexey