The two items which reappear to remind Pip of his earlier activities are the file which he gave to the escaped convict, and the leg iron which the convict used the file to remove.
The file reappears in Chapter 10. Pip goes to meet Joe at the public house, The Jolly Bargemen. There is a mysterious stranger in the bar who is most interested in Pip. Pip is alarmed to see the man stirring his drink with Joe's file:
He did this so that nobody but I saw the file...I knew it to be Joe's file, and I knew that he knew my convict, the moment I saw the instrument.
In chapter 16, Mrs Joe is brutally attacked and left for dead. She had been beaten with a blunt instrument. At her side was
a convict's leg-iron which had been sawn asunder.
The leg-iron forces Pip to think that his convict is being maliciously implicated in the crime-
I believed one of two other persons to have become possessed of it, and to have turned it to this cruel account.