The old books unfortunately in my county of Camden were getting pretty beat up by the absractors and other members of the public.  Not only did they write in the books, but they also would take them elsewhere in the vault and then not put them back...or worse yet, put them back in the wrong shelf. 

The clerks and registers in New Jersey cannot get rid of their books as they are a permanent record, but they can take them out of public circulation.  They are now just a backup system, like the micorfilm of old.  When I was a Deputy Register in Camden, I had to call National Underground storage several times to get them to send me a replacement document from microfilm because someone thought taking a mortgage out of a book would make it go away.

A couple of years ago, I got quite a surprise at one of the Pennsylvania recorder offices.  Apparently a Sheriff's deed had been recorded and they put down the incorrect corporate name of the grantee. Rather than record a corrected copy of the deed, they just switched the image in the computer and made no note of the change.  It was as if the mistake never happened, but I knew it did because my copy of the deed was different.  They made it seem like it was no big deal when I complained.