Appropriate Error Control for a Find & Delete statement - vba

Question

currently I am trying to scan my book for an if statement I wrote, where it identifies unique ID's then returns "Not in Book" if that id no longer exists.
To clean the book of all the area's where I see "Not in Book" I created a small bit of code to purge all of those entries.
Dim MWS As Worksheet
Set MWS = Sheets("Marks")
MWS.Cells.Find(what:="Not in Book", LookIn:=xlValues).EntireRow.Delete
What is the appropriate way for this statement to...
A. Scan the entire book for this phrase and delete that row as opposed to deleting one row at a time.
B. To error control this statement so when "Not in Book" does not exist the user will not get an error, rather nothing will happen or a msgbox will appear stating the book is clean.
Thanks,

Answer 1

You can do it like this. Assign the search to a range variable and check if it's Nothing.
Sub x()
Dim rFind As Range, MWS As Worksheet
Set MWS = Sheets("Marks")
With MWS
Set rFind = .Cells.Find(what:="Not in Book", LookIn:=xlValues, _
Lookat:=xlWhole, MatchCase:=False, SearchFormat:=False)
If Not rFind Is Nothing Then
Do
rFind.EntireRow.Delete
Set rFind = .Cells.Find("Not in Book")
Loop Until rFind Is Nothing
Else
msgbox "Term not found"
End If
End With
End Sub

Answer 2

I think the simplest way is a loop through your cells and check if the cell value equals your word then delete the row. Here is the code.
Sub CleanTheSheet()
dim rng as range
for each rng in activesheet.usedrange.cells ' Here you can specify name of your sheet or the range if you have such a info
if rng.value ="Not in Book" then rng.entirerow.delete
next
if worksheetfunction.countif(activesheet.usedrange,"Not in Book") = 0 then msgbox "The Sheet is Clean Now!"
END SUB