Yes, you can.

My advice would be to use a program for it. You can use something like Photopea. It is free and online.
Choose the Bucket tool, set tolerance to 0, uncheck "Anti-alias", choose the background color, and paint. The edges can be trimmed to around 13 pixels distance on all sides to be consistent. Then, you use the Rectangle select tool to carefully put a rectangle on the "a" from "Calender", right click and choose "Layer via Copy", then move the "a" to make it "Calendar".

You can also use the Rectangle select to measure distance between a sprite and the edges of the sheet, or distance between sprites, then fill it with a different paint to make it akin to a ruler, use the Crop tool, and trim down. "Layer Via Cut" can also be used to move things around more neatly, then conflicting colors can be erased, merge layers by selecting all the layers you want to do so and then right click the option, and then Bucket fill the gaps with the background colour.

Here is a link with the results, edited by me: https://i.imgur.com/dd16ubR.png

nothing i can do about that

*Calendar
*Background
There is some inconsistent blank space between the backgrounds and the sheet background that could be filled.