Are resin aquarium ornaments and ceramic caves safe for fish?

Reviewers in r/Aquariums report that aquarium-labeled resin and food-grade or kiln-fired ceramic decorations are broadly considered safe, but two recurring cautions come up: hollow legs or crevices can trap small fish, and uncertain imports should be soaked and rinsed before use. Ceramic caves marketed for shrimp, cichlids, and bettas are the most consistently endorsed because they are inert, heavy enough to stay put, and easy to clean.