Clearing out my mum's house atm and have come across old holiday money, US dollar bills, very small amounts which she says can be exchanged for the grandchildren. There wouldn't be more than $60 -$70 in total - one $20 note, pile of $5s, lots of singles. They took holidays there between 1988 and about 2004, I believe. From what I can gather, US currency never becomes obsolete within the States, but there can be problems exchanging the older notes for sterling - is this the case? Anyone advise please?