Hi, guys,
The spring clip should NOT be removed from the top handguard. Removing it is not needed for any normal cleaning, and trying to do so may break the handguard. If a handguard must be replaced, new handguards come with the clip on them and there is no reason to remove it.
One exception: If you are a collector, and want to replace a cracked handguard with a newer one but keep a grooved clip, you can remove the clip with a special tool. Other wise, leave it alone.
Jim