Tub Surround How Do I Remove Caulk From A Fiberglass Tub Surround Without Scratching The Surface?

How do I remove caulk from a fiberglass tub surround without scratching the surface? - tub surround

I'm surrounded by three pieces of fiberglass tub. Some of the sealant between the three parts are rusty, so I wanted to replace it.

I took some of the most dense with a plastic tool, remove the glue, but there are a lot of wax stuck in the cracks.

I do not use anything sharp for fear of scratching at the surface.

Thanks for any help.