This article explains how to delete products from the order guide of the Legacy Ordering app.
Once you've clicked into a vendor, you'll be able to edit your Order Guide. Tap the pencil icon in the top left corner to enter editing mode. You will see a column of red subtraction signs pop up. Tapping this icon will allow you to delete the item from your Order Guide. Tap "Save" in the top right to confirm changes and exit the Edit page.
An item can also be removed through the Product Details page. Tap on the row of any item in your Order Guide. Tap the "In Order Guide" button at the bottom to remove the item from your Order Guide. The button should no longer be grey.