“Stubble burns, gold doesn’t.”
Of course...and of course, 1 Corinthians 3 has NOTHING to do with Purgatory.
And lest anyone doubt, let them read it for themselves:
“What then is Apollos? What is Paul? Servants through whom you believed, as the Lord assigned to each. I planted, Apollos watered, but God gave the growth. So neither he who plants nor he who waters is anything, but only God who gives the growth. He who plants and he who waters are one, and each will receive his wages according to his labor.
For we are God’s fellow workers. You are God’s field, God’s building. According to the grace of God given to me, like a skilled master builder I laid a foundation, and someone else is building upon it. Let each one take care how he builds upon it. For no one can lay a foundation other than that which is laid, which is Jesus Christ.
Now if anyone builds on the foundation with gold, silver, precious stones, wood, hay, straw— each one’s work will become manifest, for the Day will disclose it, because it will be revealed by fire, and the fire will test what sort of work each one has done. If the work that anyone has built on the foundation survives, he will receive a reward. If anyone’s work is burned up, he will suffer loss, though he himself will be saved, but only as through fire.
Do you not know that you are God’s temple and that God’s Spirit dwells in you? If anyone destroys God’s temple, God will destroy him. For God’s temple is holy, and you are that temple.”
At no time does it suggest that the believer is punished or put to fire to cleanse him from any remaining sin and prepare him for Heaven.
Of course, this is not suggested ANYWHERE in the Bible, and a great many verses teach the opposite.
Mark 9:47-50 (King James Version)
47And if thine eye offend thee, pluck it out: it is better for thee to enter into the kingdom of God with one eye, than having two eyes to be cast into hell fire:
48Where their worm dieth not, and the fire is not quenched.
49For every one shall be salted with fire, and every sacrifice shall be salted with salt.
50Salt is good: but if the salt have lost his saltness, wherewith will ye season it? Have salt in yourselves, and have peace one with another.
Malachi 3
(2) But who may abide the day of his coming? And who shall stand when he appeareth? For he is like a refiner's fire, and like fullers' soap; (3) And he shall sit as a refiner and purifier of silver; and he shall purify the sons of Levi, and purge them as gold and silver; and there shall be they that shall offer unto YHWH offerings in righteousness. (4) Then shall the offering of Judah and Jerusalem be pleasant unto YHWH, as in the days of old, and as in ancient years. (5) And I will come near to you to judgment; and I will be a swift witness against the sorcerers, and against the adulterers, and against false swearers; and against those that oppress the hireling in his wages, the widow, and the fatherless, and that turn aside the stranger from his right, and fear not Me, saith YHWH of hosts. (6) For I YHWH change not; and ye, O sons of Jacob, are not consumed. (7) From the days of your fathers ye have turned aside from Mine ordinances, and have not kept them. Return unto Me, and I will return unto you, saith YHWH of hosts.
Purgatory is about purification, not punishment, so indeed the passage does not suggest that. However, man is likened to a building built of both noble and base material, and the base material burns off; the building is then freed of "the stubble", so in the analogy that St. Paul is giving us, the man who is the building is cleansed. The building materials are analogized to man's work, and some work is sinful. So that is sin that is burned off as stubble. Finally, the man is saved in the end of that process, so it does prepare him for heaven.