When I was a little kid my sister and I put our hands in the wet concrete driveway that my dad poured. I thought making a silicone mold of our handprints and then remolding them into a garden step block would make a nice Mothers Day gift. My only concern would be leaving a stain on the now owners driveway from using any release agent. I’m pretty sure I could get the homeowner to agree as long as it won’t stain their driveway. Any recommendations or advice?

Do you really need a release agent?

When in doubt, test it on something not so sensitive.

I honestly have no clue. That’s an assumption on my part.