Furniture, Wood and Cabinetry Finishing - black stain on old oak table

My husband left a bag of tomatoes on an old oak dining table recently purchased at a thrift store. Tomatoes began to decompose and leaked on table, which has almost no finish remaining. When I went out to shed to begin stripping the table I found the mess and the tomatoe 'juice' created large black stains on the wood. What can I use to remove the stain without major sanding?

It is highly unlikely you'll be able to remove the stain completely. However, here is an approach.

The rest of the finish must be removed. Apply Oxalic acid. It comes in a powder form that you dissolve in hot water. It's usually available at paint stores and hardware stores. Apply to the entire top. This is a wood bleach that must be applied uniformly so it will bleach uniformly. Any actions that result will be visible within 2-3 minutes.

It may be applied for a second and third time. After that, further applications are useless.

Oxalic acid (in its powder form) is a respiratory irritant. After the liquid dries, the powder will reform and must be removed with a wet rag - this will take several applications.