What would you recommend to remove stain around ribbed edges of table?

Depends on the type of material the table is made of and what type of stain it is. A picture would help, as well. For a general guide to removing stains from wood, check here:

1. Use baking soda on dye stains.
2. Use dish detergent for non-greasy stains.
3. Rub greasy stains with ammonia.
4. Clean pet stains with a bacteria killing solution.
5. Use isopropyl alcohol for permanent marker stains.

Use bleach to get rid of black stains.

More tips and tricks: https://www.wikihow.com/Get-Stains-out-of-Wood

An old toothbrush and they also make brass wire brushes the size of toothbrushes. I get mine at True Value, and sometimes I get lucky and get 3 packs at Dollar Tree. I also use steel wool in 00 and 000.