On this page of the Deathloop game guide, you will learn the purpose of the shiny objects that Colt may come across while exploring different locations. We explain what you will need to interact with them and what they are used for during the campaign.
You can encounter shiny objects from the very beginning of the game (example in the screenshot). Unfortunately, you will be unable to interact with them initially and they are also indestructible.
You will be able to use the shiny objects in the next stage of the game to obtain the residuum resource. However, you will first need to complete the lead/mission called Ubiquity, during which Colt will learn this technique. We described the whole process step by step on a separate page: Keeping abilities and weapons - how?. As a reminder, you will have to visit the Complex, examine Dr. Wenjie's laboratory and eliminate the visionary (boss) for the first time.
Once you have learned how to "suck out" the residuum from objects and characters, you will be able to find these objects and interact with them (Square). Each interaction will earn you some residuum, which you will then be able to use to infuse any plaques, weapons or trinkets you find.