Stoke-on-Trent City Council is working with Birmingham City Council and the Arts Fund to raise £3.3m by 17 April to buy the hoard.
The Arts Fund said £2m had been raised so far and famous names such as Dame Judi Dench and Noddy Holder had given their support to the appeal.
Monty Python star and historian Terry Jones is visiting Birmingham later to look at the hoard items on display there.
If the money is not raised, the collection could otherwise be divided and sold to private collectors.
The National Heritage Memorial Fund, the fund of last resort for the nation's heritage, is meeting on Tuesday to discuss whether to help with funds or not.
Items from the hoard can be seen at The Potteries Museum in Stoke and at the Birmingham Museum and Art Gallery until 18 April.
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