Shapeways was/is notorious in shipping purchases with release agent (an oily slick) . I wash it in water and Dawn. Rinsed thoroughly. I then placed it under a UV light in a secluded closet as UV light is dangerous to your eyes as well as curious pets. I leave it for 24 hours.

I would not recommend soaking it in alcohol. My experience is alcohol softens some 3D printing material to the point of garbage. Not good especially for fine detail parts . I use alcohol only on attachment points to prevent cutting shock on fine 3D parts with one too many attachment points.

That agent does have to be cleaned off sooner rather than later or it to will melt/warp parts. That process of washing and UV lightning works for me.