We don't measure density directly, but with volume and mass. A small fixed volume is measured with a volumetric pipet. Masses are measured by difference on a balance. Grasp from labeled side. Don't put anything into or back-into it.
Volumes are for course estimations.
You may return stuff to it. Shape prevents spilling. Cleanliness and dryness are NOT necessary. Measure tare mass. Empty to source beaker to reuse for next trial.