The rate of success depends on several factors, but, yes, often it is possible to decipher an obliteration of some information on a document.

An “obliterated writing”, or ‘obliteration’, involves some entry or information covered or obscured by some other material—ink from the same or a different pen/marker, white-out material, paint, etc. The obliteration is done in an attempt to hide or mask the original information, for either legitimate or illegitimate reasons.

There are various methods that can be used to decipher original information.  These include microscopic examination, the application of special lighting and filters (spectral examination), or various other visualization methods.

As noted above, many factors come into play in the decipherment process with success depending upon the type of instrument(s) or obliterating material involved, the nature of the substrate, the process used for the obliteration and the degree to which it is done. As a result, there are times when it will be impossible to decipher (all of) the original entry.