How to remove Wrong Cartridge error on Canon MP730

First Clean and Dry the Print Head:
I used a cotton swab dipped in 70% isopropyl alcohol (rubbing alcohol). Do not use too much alcohol.
Then dry the heads, again using dry cotton swab. Be careful not leave any cotton threads on the print heads.
Then I padded dry the spongy Ink Absorbers (one for black ink and the other for color ink) using
Separate cotton swabs for each absorber. Do not displace the absorbers. Or you can replace the ink absorbers at this point if you do not want to pad them dry.

Then Proceed to the Waste Tank Reset procedure below:

To reset waste tank full error in MP730.

1. Press the "menu": Key
2. Press "Copy" Key
3. Press "#" Key

4. Scroll thru the menu headings until you come to "Test Mode" - 12th heading or select (-) as a short-
cut to the last setting.
4a. Press “Set” and the display shows:
Test Mode [1] – [8]
CF-FH3 :WLD-11-02

4b. Press “8” and the display changes to:
Test Mode [1] – [8]
Please wait

***note*** you have to wait until the display changes

Then the display changes to:
8: PRINTER TEST
[2]---[8]

5. Then Press the "3" button and the display shows:

8 – 3 : EEPROM Clear

*** the display scrolls to [0] : INK COUNT
[1] : 2PURGE FLAG

6. Press "0" button – for INK COUNT
7. Press the "Stop" button
8. Press Off then On to set new changes.
9. Printer feeds a blank page after it is turned on again.

This should Reset the printer and remove the WRONG CARTRIDGE error and save you a few dollars.

Replace all the Ink Absorbers.
QA4-1012-000
QA4-1013-000
QA4-1014-000
QA4-1015-000
QA4-1055-000
Reset the counter to zero.

Replace the printhead. QY6-0042-000 (now QY6-0064-000)
Should cost you about $54 if in the US.

This will only work a few times. Eventually, it will fail to reset
and you will have to replace the Printhead.