Woodworkers can't remove persistent surface defects after sanding, blocking project completion

DIY and professional woodworkers spend hours sanding table surfaces only to discover stubborn spots (stains, discoloration, or damage) that won't disappear, forcing them to restart the entire refinishing process or accept subpar results. Current solutions like additional sanding, stain removal products, and online forums provide inconsistent guidance, leaving people uncertain whether to continue sanding (risking over-sanding) or try chemical treatments that may damage the wood further.