Smith and Robards trade show question

Noon, Boot: Boot your Gadget goods to discard a card and then draw a card. If that Gadget is at a location you control but do not own, that Gadget gains a control point (until the end of the turn).

Can I discard a card that is in play (such a Disgenuine Currency Press) or does it need to come from my play hand ?

It needs to be a card from your play hand