As ChuckM suggested, there are varieties of the Oosterdam cruise ship chips that depend on UV marking. The mark is the Paulson H&C and it's either there or not there.

I found only one of the $2.50's that way and it's now in the collection. The dollars were about evenly split; have one with UV and three without left after sending all those requested last week. If you need either $1: face value plus $1 postage.

The Holland America "no ship" $2.50's are all UV marked. Two left at $2.50 plus $1 postage.

Don