"Nail polish typically has nitrocellulose or another functionalized cellulose in it which forms a thin, stable film without a gap over items such as fingernails, or the capacitors you used it over. A alkyl acetate helps move it into place, and then promptly evaporates leaving behind just the thin film.
"Some nail polish formulations have benzene derivates. Toluene is a prime candidate used by some companies, which does a similar job as nitrocellulose. Look at the composition before buying or using these, as toluene isn't nice to play with even at lower concentrations."