I have a catalogue with more than 150000 (150k) unique single item pages, each with schema.org set up for titles, descriptions, images, prices etc. These pages are dynamically built through a unique ID in the URL.
Unfortunately this includes out of stock items and "old" items where some or all content required for schema.org may be empty. This results in error flags raised in Google Webmaster Tools.
What would be a better approach to tackle this catch-22?
Fake schema.org Data (i.e. Set price from NULL to "0.00"), which is NOT the correct price, suggesting the item is free of charge.
Flag the page as noindex (which may be index'ed one day and noindex the next to be index'ed a couple of days after again)
Set a 301 to another page.
Set a 302 to another page.
As it stands now, I have approximately 18.000 pages indexed with schema.org according to Google Webmaster Tools. I have the feeling that the less errors I receive caused by missing schema.org for already indexed pages, the faster Google lists the outstanding ones.
Any ideas on what the best practice would be for such a scenario?