HttpApplicationState.Remove(String) Method 
// System.Web.HttpApplicationState
/// <summary>Removes the named object from an <see cref="T:System.Web.HttpApplicationState" /> collection.</summary>
/// <param name="name">The name of the object to be removed from the collection. </param>
// Token: 0x060007D5 RID: 2005 RVA: 0x0001093C File Offset: 0x0000EB3C
public void Remove(string name)
{
    this._lock.AcquireWrite();
    try
    {
        base.BaseRemove(name);
    }
    finally
    {
        this._lock.ReleaseWrite();
    }
}
private volatile Hashtable _entriesTable;
this._entriesTable.Remove(name);

 

Hashtable.Remove(Object) Method

Remarks

If the Hashtable does not contain an element with the specified key, the Hashtable remains unchanged. No exception is thrown.

This method is an O(1) operation.