Avon makes a lotion called "Silicone Glove" that you apply to your hands before working on an engine, etc. It keeps oil and lubricants from sticking to your hands without the need for gloves, and it doesn't leave a sticky feel like other lotions can. It leaves no residue on whatever you're working on...great stuff!
Now the fingernail problem is still a problem, but I hate to work with gloves unless I absolutely have to!