Most people dump their loose change into a jar and forget about it. But what if one of those pennies could be worth $2,000… or even $20,000? 
Believe it or not, rare U.S. pennies are still being found in everyday collections—and two of the biggest sleepers are the 1990 No-Mint-Mark Proof Penny and the 1970-S Small Date (High 7) Penny.
Let’s break it down step by step so you know exactly what to look for. 
Step 1: Dump Out Your Coin Jars
Yes—start with the basics! 
Grab your penny jars, old piggy banks, or loose change trays and spread everything out on a table with good lighting.
You’re looking for specific dates and features, not just old coins.
Step 2: Look for the 1990 Penny With Mirror-Like Shine
Start by checking 1990 pennies.
What makes this penny special?
- Date: 1990
- Mint Mark:
No mint mark at all - Surface: Deep, mirror-like polish (very shiny, reflective fields)
This finish is called a proof strike, usually made for collectors—not circulation.
Why This Penny Is So Valuable
Normally, proof pennies from 1990 have an “S” mint mark (San Francisco Mint).
But a rare mistake occurred:
- Some 1990 proof pennies were struck WITHOUT the “S” mint mark
- These coins should never exist… but they do
One example sold for $20,000 at auction in 2007
Other examples have sold for over $2,000
If you find a 1990 penny with mirror polish and NO “S”, stop immediately—that could be a five-figure coin.
Step 3: Don’t Confuse It With a Regular Proof Penny
A normal proof penny:
- Has a mirror-like finish
- Has an “S” mint mark (not the rare one)
You want mirror-like polish + NO mint mark
Step 4: Check for the 1970-S Small Date (High 7) Penny
Next, search for 1970 pennies with an “S” mint mark.
There are two varieties:
- Large Date
- Small Date (High 7) ← the valuable one
Step 5: Identify the “High 7” Small Date
The key difference is the number 7 in “1970”.
Small Date / High 7:
- The 7 sits higher
- The top of the 7 aligns closely with the 9
- Numbers appear tighter and more compact
Large Date:
- The 7 sits lower
- The date looks wider and more spread out
Pro Tip:
Use your smartphone 
- Zoom in closely
- Take a photo
- Draw a straight reference line in your photo editor
This makes it much easier to see if the 7 is high or low.
Auction Results That Prove the Value
- 1970-S Small Date Penny
Sold for $2,400 - Other examples regularly sell for $2,000+, depending on condition
Final Thoughts: Check Every Penny Carefully
Most people overlook pennies—but collectors know better.
A single coin from a forgotten jar could pay for:
- A vacation
- A new car
- Or a major investment
So before you spend or ignore your change:
Check your 1990 and 1970-S pennies carefully
You might already be holding a small fortune.
