Adding controls to a VBA Collection

I am trying to add specific form controls to a VBA collection, so that
I can pass the entire collection to another function, and access the
individual controls later. I have tried several different syntax
variations. In each case, the receiving function produces the error
'Object Required' when I try to access any property of a control in
the collection. If I reference a collection item in the debugger
using its ordinal position, I see the value of the control. So, on
the surface at least, it appears that I am only adding the control's
'value' to the collection, not the control itself; or maybe my syntax
for retrieving the control's properties is at fault. Any help would
be greatly appreciated.

Dim colControls As Collection
Dim ctl As Control

Set colControls = New Collection

'I've tried this
Set ctl = Me.txtDosage
colControls.Add (ctl)

'And this
colControls.Add Me.controls("txtLabel")

'And this
colControls.Add Me.txtLabel


'The code to receive the collection look like this
Public Function fcnLogAudit(lngRecordType As enuRecordType,
lngRecordKey As Long, _
colControls As Collection) As Boolean

Dim ctl As Control

'Error occurs on this line. If I look at ctl(1) I can see the
control's
'value, but I can't access any of it's properties
For Each ctl In colControls

If ctl.Text <> ctl.OldValue Then...
.

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