Can I use this cream on other dry areas like elbows, knees, or hands, or is it only for feet?

The formula isn't foot-specific in a way that restricts it to feet. Cocoa butter, shea butter, urea, and sea buckthorn oil are all common in body care for any thickened, dry skin. Elbows and knees have similarly thick stratum corneum and few sebaceous glands, so they respond well to the same occlusive and humectant combination. Apply a small amount after bathing while skin is still damp. For hands, the cream will certainly moisturize, but the soy wax and butters give it a noticeably richer, slower-absorbing finish than typical hand creams. This makes it excellent as an overnight hand treatment (apply generously, wear cotton gloves), but it may feel tacky under keyboards or tools during the day. If you already have the tube open for feet, using it on elbows or knees avoids buying another product. Just avoid applying urea-containing products to freshly shaved legs, sensitive facial skin, or areas with active irritation — the stinging risk is higher there.