Question

What can you do to oil and water so that they can dissolve?

Answer 1

In each other? Add a surfactant -- a compound that, roughly speaking, interacts favorably with both. They won't really dissolve, but they can form an emulsion, in which one will be evenly distributed in tiny globs throughout the other. The most famous example is mayonnaise, which is an emulsion of oil in water (vinegar), with eggs providing the surfactant.