Delete missing component

Hi, 

we had a contracted designer who works in solidworks and he supplied all data in native SW format. That is fine. Model opens just fine but there are some components missing. It is just some screws from his toolbox which we do not require.

I want to just delete them off the assembly but I dont know how. When I right click on the part in assembly tree there is no Delete option. Is it even possible to delete it? Thank you.