Problem with "Contents" rule

Hello.
I am brand new to Hazel, and I'm trying to learn how to use the tool. It appears that it could be very useful, especially for scanning/filing documents. Unfortunately , I am running into a problem using "Contents" as part of my rules. Here is the latest example:
I download a file from PayPal. The file is named Download.csv. I can use Hazel to find the file, move it to the correct Folder, and rename it. All of this works just fine.
However, the potential for other files named Download.csv is high enough that I decided to ensure I'm grabbing the right file by checking the "Contents" of the file. So, I made a rule that looks for:
"Contents contain match Express Checkout"
Hazel no longer sees the file as a match even though this text string appears many times within the file.
I've also tried "Contents contain match Express" and "Contain Express" Neither of these work either.
What am I doing wrong?
I am brand new to Hazel, and I'm trying to learn how to use the tool. It appears that it could be very useful, especially for scanning/filing documents. Unfortunately , I am running into a problem using "Contents" as part of my rules. Here is the latest example:
I download a file from PayPal. The file is named Download.csv. I can use Hazel to find the file, move it to the correct Folder, and rename it. All of this works just fine.
However, the potential for other files named Download.csv is high enough that I decided to ensure I'm grabbing the right file by checking the "Contents" of the file. So, I made a rule that looks for:
"Contents contain match Express Checkout"
Hazel no longer sees the file as a match even though this text string appears many times within the file.
I've also tried "Contents contain match Express" and "Contain Express" Neither of these work either.
What am I doing wrong?