Thank you for your feedback.
Actually there is no easy way to clear the value of the RadMaskedTextBox control using only the Web Aii framework. There is no particular method in the RadMaskedTextBox's wrapper for this particular purpose.
Anyway I can suggest you several workarounds which should help you to achieve the desired result.
1. The simplest way is just to clear "manually" the value of the RadMaskedTextBox using the Web Aii framework.
You could have something like:
where the number of spaces in the "TypeText" method is equal to the length of your RadMaskedTextBox.
2. You can set explicitly the "Value" property of the RadMaskedTextBox to "string.Empty" or "null".
3. You can set the property of the RadMaskedTextBox control "SelectionOnFocus" to value "SelectAll". Thus anytime the RadMaskedTextBox gets the focus its content will be automatically selected and any typing in it will replace the previous content.
I hope that some of the above solutions will help you to successfully achieve your goal(s).
Please, don't hesitate to ask if you have any additional questions/comments on the subject.
All the best,
the Telerik team