How can I delete linked transactions before Jan 1, 2020

Thanks for reaching out to the Community forum, brian138.

Let me get the help you need in managing your transactions. 

To start, I'd like to verify if the linked transactions were added from the banking screen? If yes, you'll need to Undo them first so they will show up on the For review page. From there, you can exclude them by batch. 

Here's how:

1. In the left menu, click Banking or Transactions page. 
2. Go to the Banking tab and select the bank account.
3. Tap the Categorized tab. 
4. Select multiple transactions that need to be excluded.
5. Hit Undo button. 

Then, to exclude transactions, let me show:

1. In the left menu, click Banking or Transactions page. 
2. Go to the Banking tab and select the bank account.
3. Tap the For Review tab. 
4. Select multiple transactions that need to be excluded.
5. Hit the Exclude button. 

Once it's excluded, it'll now be transferred to the Excluded tab in which you have the option to delete it. 

If it's manually added transaction, you can manually open it one at a time and delete them.

You may want to visit this article to learn more about excluding transactions: Exclude a bank transaction you downloaded into QuickBooks Online.

To help you manage your bank transactions and reconciling your account in QuickBooks, you can visit this link: Banking. 

Please know that I'm only a few clicks away if you need anything else. Cheering you to continued success. Have a great day.