I never heard of this method before today. Is there a problem with the safety, or is this okay to do? This article lists three methods.

1. Alternating layers of fresh herb leaves and salt

This is by far the easiest method. In a clean glass jar add a layer
of salt to cover the bottom. Add herb leaves in layers, alternating with
the salt, until the container is full. Refrigerate.

The leaves will stay surprisingly fresh and flavorful for months. To
use, just remove a leaf and brush off the salt. As an added bonus, the
salt will become flavored over time and can be used in cooking too.

2. Grind & Dry Method

Use a ratio of 1 part herbs to 4 parts salt for the grind and dry
method. Clean and dry fresh herbs and chop them into small pieces until
you have 1/4th of a cup. Place them in a blender or food processor and add 1 cup of salt. Process until they are completely incorporated.

Lay the mixture out on a baking sheet and cover with a cloth, keeping
it out of direct sunlight. After a day, place the mixture into a clean
glass jar and cap tightly. Keep in the refrigerator until needed. It
will last for one year.

3. Chop & Stir Method

Use a ratio of 4 parts herbs to 1 part salt for the chop and stir
method. Clean and dry fresh herbs and chop them into small pieces. You
can add them to a food processor, coffee grinder, or glass bowl.

Add one part salt to the herbs, pulsing in the food processor for
about 30 seconds. This will create a distinctly herb smelling salt that
will take on the color of your herb. It is the most fragrant of the
herbed salts we are making today.

Here's a link to the full article.

Preserve Basil in salt...

Thanks, Jill