What technique is commonly used to remove excess product from the surface of the nail?

Filing is the technique commonly used to remove excess product from the surface of the nail, particularly in nail enhancement procedures. This method involves using a file to shave down the top layer of product, which allows for a smoother finish and the ability to shape the nail accurately. It helps in fine-tuning the nail's edges and overall appearance after applying materials like acrylics or gels.

While other techniques such as buffing are used to smooth the nail surface and add shine, buffing does not primarily serve to remove excess product. Cutting generally refers to trimming the nail or skin, which does not apply to refining product layers. Sanding is often associated with more intense abrasives and isn't typically used for finalizing nail enhancements. Filing remains the standard and safest practice for achieving a well-finished look on the nail surface.