Is it hard to claim forks?
Not really. As you google it, you just have to follow instructions as long as your wallet is eligible for that airdrop. There are services that's dedicated for claiming forks here in the forum that you can avail.
Is there risk claiming forks?
Like FatBen mentioned, if you downloaded the wrong claiming software your computer might be infected by a malware. This is why you have to verify what are those legit sources that you need to download for those forks you're about to claim.
Are there forks that are worthless?
There's a lot.
What are these forks you think your wallet is eligible with?