I can help you cleat those previous balances, @sc38.

Creating journal entries can help in clearing those accounts when running your reports like the Balance Sheet. What I can suggest is you to record a tax payment to clear those previous balances.

Here's how to manually record your tax payment to zero out your GST payable:

1. Go to Taxes and proceed to the Returns tab, under Filed returns, find the return and select Record payment. 
2. Add the Bank account, Payment date, and Payment amount on the Record Credit Card page.
3. Select Save.
4. Your return is now marked as Filed and paid.

You can see your payment details under the Payments tab.

Here's the file your GST return and record tax payment in QuickBooks Online article for detailed guidance. 

You can also refer to the following article on how to record, adjust and delete GST payments in the GST Centre: Manage GST payments in QuickBooks Online.

Let me know if you need further guidance in clearing out your balance. I'm always here to help you out. Take care and have a great rest of the day!