First of all, I would like to warn you that what I am suggesting should be treated as just a quick and dirty way of POSSIBLY solving your problem. I'd seriously recommend a proper clean lube and adjust by a pro technician as early as you can afford. But the following has worked for me - read: I have done this successfully on two 60s/70s Compur shutters. The main piece of advice is to USE CARE (BE GENTLE, USE COMMONSENSE). And certainly, remove the front and back optical groups before you proceed.

I have found lighter fluid to be a VERY TEMPORARY solution. It's more of a salesperson trick than anything else to get a shutter going for a while. As long as the fluid is present, the shutter will work ok. But once it dries up again (which is usually within a day or two), your shutter will either be worse off or be back to the same condition. Shutter mis-timings can be due to at least 3 things: 1. Oil on shutter blades (as you have described); 2. Springs on the timing mechanism that have lost their proper tension' 3. Dried up lubricant within the gear train itself.

Oil on aperture and shutter blades is not too difficult to clean off. The best solvent I have come across for this the now banned solvent 1,1,1 trichloro (WARNING: inhaling its fumes will damage your insides). I can still buy this as "Liquid Paper Correction Fluid" solvent from stationery shops in my country. Apply some to cotton buds (Q-tips?) and gingerly clean the blades when they are closed. Do not bend the blades by using too much force. If your shutter has a preview feature, open the blades halfway after you have cleaned them already to get at the areas where you didn't get to when the blades were fully closed. I have also done this on a Supermatic and it cleaned up nicely. Ideally, you'd re-lubricate the shutter blades with graphite lubricant but this probably best done by a pro.

If 1,1,1 trichloro is unavailable, you can use ethanol - get as pure as possible. My experience with using lighter fluid here is that it merely spreads the grease around without actually helping to clean it off.

I cleaned the shutter and aperture blades on 2 older Compur and one Kodak Supermatic this way and they work wonderfully now.

If its a spring tension issue, then you either have to get the shutter overhauled by a specialist (like SK Grimes), or use the shutter as is by compensating for the off-speeds. You'd still have to somehow get the real speeds timed so you'd know how much to compensate for.

The last possible solution must be done with the utmost of care. In my experience, dried up lubricant on timing gears can be tackled quite easily with a miniscule amount of WD-40. That's right - that humble can of do-it-all spray.

THE MAIN THING TO NOTE IS THAT YOU NEED ONLY A MINISCULE AMOUNT, and I do mean as little as possible. Practise squirting the smallest amount that you can on a tissue (not even a squirt - a teeny little sneeze). Where should you poke that red tube? Most problem shutters with slow speeds that are off can be revived by spraying a very small amount into the slot where the cocking lever is. With the cocking lever in the untensioned state, spray the least possible amount in there. Cock once, and spray the other side. Again, as little as possible. Cock and fire your shutter at all shutter speeds for a few cycles. You'll find that the slow speeds have been revived. The danger when you overdo it is that the WD40 gets all over your shutter and aperture blades. You DO NOT WANT THAT. Leave the shutter out in the open and let it air out for a while before you screw in the lenses.

My two old Compur shutters revived this way have worked perfectly for over a year. Speeds are all on the mark. I would however be sending them for a proper CLA when I can be bothered to do so.

Another word of caution - do not attempt what I have suggested on Compound, Ilex or Rapax shutters.