MS Excel
If you need to remove only the formatting done in a range (numbers and formula typed there should not be removed), you must

From Edit menu choose Clear and then Formats
Click on Remove Formatting tool on Standard Toolbar
From Edit menu choose Delete
Double click the Format Painter and then press Esc key in keyboard

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MS Excel
When all the numbers between 0 and 100 in a range should be displayed in Red Color, apply

Use =if() function to format the required numbers red
All of above
Apply Conditional Formatting command on Format menu
Select the cells that contain number between 0 and 100 then click Red color on Text Color tool

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