These are 3d resin printed, high detail models. As resin is delicate, if they do break all you have to do is use thick super glue to put them together again - but I'm sure you already know that being a hobbiest like you are! These may come on printing sprues, shipping sprues, or already apart. To help remove printing sprues wash part under hot water to warm it up. The sprues are the smallest connecting points on the model and will break off easy, especially when warmed up. All of these models are cured before being shipped, in rare cases a model may arrive with some residue on it. It is not uncured resin but dirty alcohol wash residue and can be washed off in warm soapy water.