[Solved] how to clear project cache memory?

It sounds like you need to remove some data from NSUserDefaults.

From This answer on StackOverflow:

The easiest way to clear NSUserDefaults is by using one of the following:

Option 1

[[NSUserDefaults standardUserDefaults] setPersistentDomain:[NSDictionary dictionary] forName:[[NSBundle mainBundle] bundleIdentifier]];

Option 2

NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];
[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];

Or if you’re using Swift:

if let bundleID = Bundle.main.bundleIdentifier {
UserDefaults.standard.removePersistentDomain(forName: bundleID)
}

Removing a single entry

To remove a single entry from NSUserDefaults, use the following:

[[NSUserDefaults standardUserDefaults] removeObjectForKey:@"preferenceName"];