Most examination bodies and academic institutions conducting OMR based aptitude tests prefer the use of pens over pencils, for filling the OMR sheets. This makes it difficult and almost impossible to erase incorrect markings on the OMR sheets, as using a pen eraser is likely to thin and damage the OMR sheet. While Addmen OMR software can facilitate the use of whiteners, this is not supported by other OMR software. It is advised that you double-check your answer before marking the bubbles, especially if you are using a pen.
If you’re marking the bubbles using a pencil, remember to erase the marks completely, so there are no smudged marks, which may be considered as a stray mark by the OMR software.
Use a soft, good quality eraser to ensure pencil marks are rubbed off completely without causing any damage to the OMR sheets. Ensure that you blow away all the rubber dust derived from erasing.
Get rid of any smudges on or around the bubbles, to avoid detection of double marking.
Never attempt to erase pen marks, as it may create holes or damage the sheet, rendering it unfit for automatic evaluation. Moreover, pen marks are difficult to get rid of completely.
Read the instructions on the sheet carefully to understand the limitations surrounding the use of erasers and whiteners.