How do I save an outdoor marbel slate from stains?

[jaelle_n_gilla]

I have recently moved an old marble table outside to our terrace and it will be sitting in sun, wind, rain, and snow all year long. Also, falling leaves and petals.

I know from indoor experience that it stains when stuff is allowed to sink in for a while. It's polished marble but Id like to make sure it's sealed.

There are several marble sealing polishes around here but I was wondering if anyone had any experiences with something natural and non-poisonous, like oil or even some kind of glue or something. Any ideas? Any recommendations?

Thanks!