It is important to be very careful when trying to remove stains from limestone countertops, as the stone is porous and can be easily damaged by harsh chemicals. It is best to use a mild, pH-neutral cleaner specifically designed for limestone.

Some recommended options for removing stains from limestone countertops include:

1. StoneTech Oil Stain Remover: This is a heavy-duty stain remover designed specifically for removing oil-based stains from natural stone surfaces. It is safe for use on limestone countertops and is effective at removing a range of stains, including cooking oil, grease, and tar.

2. Granite Gold Stain Remover: This is a non-toxic, biodegradable formula that is safe for use on all types of natural stone, including limestone. It is effective at removing tough stains, including wine, coffee, and other food and beverage spills.

3. MB Stone Care Stain Remover: This is a professional-grade stain remover that is safe for use on all types of natural stone, including limestone. It is effective at removing a range of stains, including oil-based stains, rust, and hard water stains.

4. LTP Stain Remover: This is a pH-neutral, water-based formula that is safe for use on all types of natural stone, including limestone. It is effective at removing a range of stains, including oil, grease, and dirt.

Before using any stain remover on your limestone countertops, be sure to test it out in a small, inconspicuous area first to ensure it does not damage or discolor the stone.