My question is this, after you activate the seal can you Special summon monsters from other places?
The Seal of Orichalcos destroys all monsters that you had special summoned when it activates and It specifically calls out that you can't from your extra deck.
When this card is activated: Destroy all Special Summoned monsters you control. You cannot Special Summon monsters from your Extra Deck.
However once the card has been out on the field can you Special summon again or is the effect continuous and would destroy any addition Special summoned monster?