I've got a coin hidden under a heavy object so I've set it to hidden and invisible.
When the object is moved the coin should be visible and takeable so I use the code

msg <When you try to take the terminal you find that it is actually too heavy. However, you notice an old coin underneath it.|n|nYou carefully put the terminal down, making sure that you can still get the coin.>
show <Coin>
reveal <Coin>

When I lift the object the coin becomes visible but I still can't take it.
Am I missing something?

I'm no pro, but...
If you mark the object (coin) as takeable from the beginning, it should remain takeable when the script tells it to be 'revealed' or 'accessible'. In other words, when you create the coin, mark it as 'takeable' and 'unavailable' as opposed to 'invisible' because when an item is 'inaccessible' (unavailable), you shouldn't be able to see it anyway.
Then, when the heavy object is moved, then make the coin 'accessible' in the script. You should end up seeing the coin in the room afterwards. In fact, your code might be working, you just still have it marked as invisible so you wouldn't see that it's working.

steve 8)

It's amazing how obvious it looks once you've been told.
All I had to do, as you suggested, was to change the original untakeable to takeable and now it works like magic.
8)
Thanks a million

you're welcome a million!

steve