So you want Views to exclude some nodes from your view. Easy enough right? Just go to your view and  below filter click 'add' and select 'node id' and.... but wait a second! Now I can only filter just one node! How impractical... I need to filter at least a couple of nodes! No worries, there is a solution you just need to know where to look.

1. In your view go click open the 'Advanced' options on the right side.
2. Click 'Add' next to 'Contextual Filters'.
3. Type 'nid' in the search box filtering the results to just 'Content: Nid'.
4. Check the box.
5. Below click 'Apply (all displays)'.
6. 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'.
7. Now for the magic: At the bottom click on 'More'.
8. Check the box 'Allow multiple values' and 'Exclude'.

Voila! Multiple nodes are now excluded.

Drupal 7ViewsContextual filters