What kind of cameras did you obtain? (post a pic of them if you have one)
You need to be careful with solvents on older cameras. Older cameras often use cements, glues, or plastics that may be damaged or dissolved by some cleaners. When I restore old stuff I always start with room temp water and Q-tips. If there is serious gunk you can move to heavier solvents and cleaning methods. On metal and uncoated glass I have had good luck with naphtha. Naphtha can also aid in thinning out any gummed up oil that may be on the mechanisms and free up slow or clogged operation. You should take care when using naphtha as it may thin out the gummed oil and seep into the lens elements. For just cleaning glass I like the alcohol free lens cleaning solution. Works nicely and never leaves a trace. You should take care around the shutter mechanisms and mirrors when cleaning as they are easy to damage.
In your case you may really need to get into the camera if you are prepared to open it up a bit you may have better luck than simple surface cleaning.
If you have any cameras that have a cloth bellows (like an old kodak folder etc) you may have a hard time cleaning those.
Are you intending on use these cameras or just keeping them as display pieces?
Regards
Dave