Question: While preparing coffee in my 2-cup moka pot, I usually try to carefully sprinkle ground coffee from my grinder into the funnel of my pot. When I reach approximately the amount of coffee needed to fill it, I use a knife with a straight spine to level and tip off any excess coffee, which usually wastes some of the coffee, as it tends to fall everywhere around the funnel.

Are there any tools that can make this process cleaner?

Answer: 
Short answer is no, though you can use a common kitchen scale to minimize (but not eliminate) waste. Measure in grams if you're not already and if your scale supports it for greater precision.

The basket on your pot has a fixed volume. Coffee within a particular roast batch will also have fairly consistent density. This means that you should be able to use very nearly the same "weight" of coffee per brew. Measure your coffee with a kitchen scale to get an idea of how much it takes to fill the basket, then in the future grind or scoop that amount in weight including the excess you will later level off.

Leveling off is important. If you don't level off your basket with a moka pot, you'll significantly increase the volume of steam required to produce enough pressure to push the coffee up the tube. That's bad because it'll add some variables into your brew routine that are impossible to control. Use more heat or brew longer to get more steam and you could burn your coffee, but because you wouldn't get the same surface distribution with each brew, the amount of steam you need would change per brew.

So look at it like this: dumping 1ish gram of coffee grounds per brew is not nearly as bad as dumping an entire dose because you ruined your brew.

If you're really worried about dumping that bit, get yourself an airtight food canister and use it to store leftover grounds for your next brew. That coffee will go stale right quick, but since it's such a small amount, it won't dramatically affect the next brew regardless. Waste nothing if you save what you level off!
A convenient and cheap solution is to use a coffee dispenser like this one:

[![enter image description here](https://i.stack.imgur.com/oh294.png)](https://i.stack.imgur.com/oh294.png)

The bottom of the can has steps of various diameters to fit the most common moka sizes. You put the can onto the moka funnel, turn the knob once (this opens a small door on the bottom) and then turn the knob back. In two seconds you have filled the moka without wasting any of the coffee.

Dispenser are sold empty and can be used many times, they last virtually forever since they have few moving parts and no electronics ;). Zero waste.