Mailbox Signs

Using the Keyword(s) filter:

Multiple words exclusive: use + sign in front of every word
eg. +red +pajamas - this will ensure only matches containing both words

Multiple words inclusive: just type the words
eg. red pajamas - this will bring up records containing either or both words

Exclusions:
eg. -(white sox) - this will exclude matches containing either words
eg. -("white sox") - this will exclude the exact expression white sox

Wildcards
eg. Bost* - will include all records containing words like Boston

Exceptions:
You will get no results if using a wildcard for exclusions.
eg. -bost* - this is such a case