- In your view go click open the 'Advanced' options on the right side.
- Click 'Add' next to 'Contextual Filters'.
- Type 'nid' in the search box filtering the results to just 'Content: Nid'.
- Check the box.
- Below click 'Apply (all displays)'.
- Click on 'Provide default value' and enter the ID's of the nodes you want to exclude separated by a comma like this: '23,28,30'.
- Now for the magic: At the bottom click on 'More'.
- Check the box 'Allow multiple values' and 'Exclude'.
Voila! Multiple nodes are now excluded.