Abee4u,
It sounds as though you are using the sink as the operator for the SEO. Use a solid element, such as a slab equal to the plan dimensions of the sink, as the operator and then place it on a layer that you can turn off once the operation is complete. This will remove all the counter where the sink is including the material in the bowl.
Note, that you cannot delete the operator element. It must remain part of the model or the hole you make will be deleted.
HTH
Erich
AC 19 6006 & AC 20
Mac OS 10.11.5
15" Retina MacBook Pro 2.6
27" iMac Retina 5K