Upvote:4
A poor rate of exchange is just the price you pay for having coins instead of notes. Coins are more fiddly to deal with and smaller value, so exchange places don't want to deal with them.
However, since the UK and Ireland share a land border, it's relatively easy to find someone who is likely to be travelling from Ireland to Northern Ireland.
Your options are really
Upvote:5
could I exchange [British coins] when I land [in LA]?
No. There's no business which provides that service there.
USA Today say
"Travelers returning from an international trip often have a handful of coins left over from their international purchases. While most foreign exchange companies and large banks are willing to buy back international bills, finding a home for unneeded coins is a bit more challenging."
They go on to suggest
None of these meet your criteria.
One thing to be aware of is that the old-style £1 coin was forged on a large scale. At one time about 1 in 20 was a forgery. You almost certainly have one or more forged £1 coins in your £200.
If your friend was not a close friend but a recent acquaintance, or if the collection is of coins that they accumulated because the coins were refused in coin machines, you might have more than a few worthless coins in that £200.
If anyone at an airport offered to sell me £200 in coins, I'd assume it was a probably a scam and that the coins were mostly worthless.
USA Today's suggestion of selling them to collectors seems odd to me. Any serious collector of coins will want mint-condition uncirculated coins and interesting or rare coins. I doubt any of your collection fall into those categories.