When surveying, what is the recommended action?

Tilting the cast during surveying is a recommended action because it allows the operator to determine the undercut areas more accurately. Surveying is a technique used primarily in the context of dental prosthetics, where the goal is to analyze the shape and contours of a dental cast. By tilting the cast, practitioners can visualize how the rest of the components, such as partial dentures, will fit into the oral cavity. This helps in identifying any undercuts that may interfere with the proper placement or retention of dental prostheses.

The other options, while related to proper cast handling and preparation, do not directly pertain to the surveying technique. For instance, cleaning the cast thoroughly is important for ensuring that there are no contaminants that could affect the survey results, but it does not provide the necessary insights into undercuts. Moving the cast horizontally can impact the assessment of the cast's features without yielding the desired angle required for effective surveying. Removing excess material can help in refining the cast but is not the primary action taken during the surveying process itself. Therefore, tilting the cast is the most appropriate method for the surveying action.