Black gel pens with permanent, pigment-based, nonerasable ink are the recommended choice for writing checks, because the ink resists the chemical removal behind most check washing.
For the full breakdown, see our best Pen for Check Writing guide.
Check washing — where a thief lifts ink with household chemicals and rewrites the payee or amount — is the fraud a pen choice directly defends against. The right ink makes erasure dramatically harder; the wrong one, or a pencil, invites it. Here’s what to write with, what to avoid, and the mailing habits that matter just as much.
Why Ink Type Matters More Than Brand
Ink chemistry, not brand, protects a check. Indiana’s cybersecurity guidance explains that pigment-based inks are harder to remove with readily available chemicals, which is why it recommends black or nonerasable gel ink. Typical ballpoint ink is dye-based and sits closer to the paper surface, where solvents reach it easily. Gel and pigment inks bond into the paper fibers instead — which is why the Consumer Financial Protection Bureau advises a permanent black marker or black gel ink.
Color matters too. JetPens notes black ink is easiest to avoid problems with, and warns that very light, unusual, or erasable inks create real risk. An erasable gel pen is a particularly bad idea: the formula’s whole point is that the ink can be lifted.
What to Avoid and Why
Pencil and erasable ink leave the check effectively open to editing.
- Pencil — no chemical removal needed; it rubs away.
- Erasable gel pens — formulated so the ink can be lifted, exactly the vulnerability check washing exploits.
- Light or unusual ink colors — harder to read and easier to alter unnoticed.
- Standard dye-based ballpoint — not the worst option, but it dissolves under solvents far more readily than pigment ink.
If you want a dedicated pen, a roundup of the best options framed around ink safety is worth a look before you settle on one.
How to Fill Out a Check So It Can’t Be Altered
The pen is half the protection; how you fill out the check is the other half. Leave no blank space a thief can use.
- Use black permanent or nonerasable gel ink for every line.
- Write the payee’s full name on the “Pay to the Order of” line, then draw a line through the remaining space.
- Write the numeric amount as close to the left edge as possible, and draw a line through the unused space.
- Write the amount in words and draw a line through the leftover space so it can’t be extended.
- Sign the check, and keep the memo line free of sensitive personal information.
- Record the check number, payee, amount, and date for later reconciliation.
Those lines through blank space are the cheapest way to close off the most common alteration trick.
Mailing, Monitoring, and Missing Checks
A securely written check can still be stolen in transit. The CFPB advises dropping mail directly at the post office, checking your mail often, and never leaving mail in the mailbox overnight. Mail from a curbside or unsecured home mailbox is far easier to intercept. Review account activity regularly so a missing or altered check surfaces fast — speed improves the odds of stopping fraud and recovering funds. If a check disappears, Indiana’s guidance is blunt: contact your bank right away and request a stop payment.
| Habit | Why It Protects You |
|---|---|
| Write in black permanent or nonerasable gel ink | Resists the chemicals used in check washing |
| Draw lines through blank spaces | Blocks added names or altered amounts |
| Keep the memo line free of sensitive details | Limits what a thief can learn from a stolen check |
| Mail from inside the post office | Reduces mailbox interception |
| Review account activity often | Catches fraud before it spreads |
| Report a missing check immediately | Improves the chance of a stop payment and recovery |
| Log check number, payee, amount, and date | Makes reconciliation and fraud detection possible |
Common Questions
Is a regular ballpoint pen good enough for checks?
Better than pencil, but not the strongest choice. Standard ballpoint ink is dye-based and sits near the paper’s surface, so washing solvents reach it more easily. Permanent or pigment-based gel ink resists removal better. If a ballpoint is all you have, use black and still fill every blank space.
Should I use a permanent marker instead of a pen?
Yes. The CFPB specifically advises a permanent black marker or black gel ink. Marker ink is pigment-based and soaks into the paper, resisting chemical removal. The trade-off is bleed-through and a thicker line, so many prefer a fine-point permanent marker.
Does the color of the ink really matter?
Black is the safest default. JetPens notes black ink is easiest to avoid problems with, while light or unusual colors are harder to read and easier to alter unnoticed. Distinctive colors can also complicate automated check processing. Unless you have a specific reason otherwise, black permanent or nonerasable gel ink covers readability and fraud resistance.
Sources
- Consumer Financial Protection Bureau. “What are some classic warning signs of possible fraud and scams?” Recommends permanent black marker or black gel ink and mailing checks at the post office.
- State of Indiana Office of Technology. “Writing a Check: Using the Right Pen, Avoiding the Mailbox Just the Start to Safe Check Cashing.” Explains pigment-based ink resistance and stop-payment steps.
- JetPens. “The Best Pens for Writing Checks.” Notes black ink is easiest to avoid issues with and warns against erasable gel pens.