Those darn homophones! They sound alike but their respective meanings are so completely different, that if you mistake one for the other, your beautifully constructed phrase misses the point completely.
To avoid catastrophe, you must examine your usage of the verb. When conjugating the past tense, make sure you're not referring to the metal.
Let us begin with a definition from Merriam Webster's Dictionary:
1 a: to guide on a way especially by going in advance b: to direct on a course or in a direction c: to serve as a channel or conduit for.
1: a bluish-white soft malleable ductile plastic but inelastic heavy metallic element found mostly in combination and used especially in pipes, cable sheaths, batteries, solder, and shields against radioactivity.
Lead is a wonderfully versatile verb, but its usage in the past tense can often be confused with the noun; as they are pronounced the same but are spelled differently and mean two completely different things.
Lead - pronounced leeed, to rhyme with reed, deed, steed etc. is used in the present and future tenses.
"You can lead a horse to water, probie," quipped Tony. "Just pinch your nose and swallow, okay?"
Kate stumbled again. The bleeding was slowing now, but there was a faint trail of droplets leading straight to her current position.
"He was leading an AA meeting at the time, sir," said McGee. "His alibi is pretty tight."
"Are you sure you want to lead with that?" asked Tony, peering over the top of the cards fanned in front of his face. "I know you've got that seven of clubs, so why don't you just go ahead and play it already."
"Got me that lead yet, Abbs?" Gibbs asked, as he dangled a super-sized cup of Kaff-Pow just in front of her line of sight.
"And that line of questioning will lead us right back to where we started, Jethro." Jenny frowned and looked away, refusing to meet his eyes.
Led - pronounced to rhyme with bed, red, fed etc. is used in the past tense.
"The hairline fracture present on the occipital bone led me, at first, to believe this man had died from a particularly sharp blow to the head," said Ducky. "But that simply wasn't the case."
"You'll want to check this out first." The petty officer led them along a faint trail in the undergrowth that was littered with debris from the crash.
"Breathe through your nose and out your mouth, Tony," Kate shouted over her shoulder, as she led him around the course at a punishing pace. "You sound like a dying cow back there!"
McGee tucked his chin in and led with a left right punch combination. His first fist grazed the man's cheek, but he was satisfied to hear the sickening crunch of broken bone as the other connected with the nose.
"It was the accumulation of a series of small, incidental events that led to the loss of nine lives, ma'am," said the marine. "You can be sure it wasn't anything deliberate."
"She's a black widow, boss," said Tony. "I'm sure she's led many unsuspecting men to their admittedly pleasurable but nonetheless early deaths."
Lead - pronounced to rhyme with bed, red, fed etc.
"Lead poisoning," Abby declared emphatically. "Probably ingested through his food or drink over a long period of time. Unless of course he went around licking the paint on some very old houses, we can't discount that yet."
It fitted reassuringly into his hands. A lead pipe was a crude, but effective weapon at close range.
Lead (the metal) and led (past tense of the verb) are pronounced the same, but have very different meanings. The confusion between the two probably comes from the similar sounding verb "read" (ie. I read mostly romance novels, but last week I read a biography on Einstein.) where the conjugation of the past tense doesn't involve a change in spelling.
So, to check if you are using the correct conjugation of lead in the past tense; ask yourself: "am I describing the heavy metal?"
No? Use led.
Yes? Use lead.