Soft pastels are compressed sticks of powder applied to textured papers that bring strokes of intense colours. Once applied, artists perform blending techniques to further create their piece. So, erasers to remove any unwanted markings need to have unique features. Putty or kneaded erasers are an excellent choice. You can explore the Prismacolor brand for the same. These kinds of erasers can easily pick the pigments from deep-textured papers. Some artists even keep bread pieces with them to do a clean job of erasing.