Open the folder you’d like to delete those items from and tap and hold one of the receipts from the listed view. After about 1 second, you’ll notice three new options appear at the bottom of the screen.
Once you enter this editing mode, you can go down the transaction list selecting the items you’d like to delete. Once they’re all selected (indicated by the blue checkmark to the left of the merchant name) just tap on the red trash can icon in the bottom left of the screen.