Follow this quick tip and learn how to transform any plain font into a grunge font using only some of the many Art and Scatter Brushes available in Illustrator along with a dose of creativity. I will demonstrate the method using two different types of fonts. Let’s begin!
Step 1
Open a new web document. Take the Type Tool (T) and type "Vector" then from the Object menu choose Expand and Ungroup. Copy and Paste in front all the letters, remove the fill color and stroke them using any color you want. Next go to Object menu > Compound Path and select Release.

Step 2
Now you have to cut these paths. Take the Scissors Tool (C) and click on the indicated anchor points to cut them. I colored the resulting segments so you can see them better. The points indicated at the bottom of the letters "V" and "T" are added using the Add Anchor Point Tool (plus key) because I needed a point in the middle.

Note: It’s not mandatory to use exactly these points, it’s important just to obtain different segments that you will need further. The end result will be similar.
Step 3
Select all these colored segments and Stroke them using an Art brush called Charcoal-Rough that you can find in the Brush Libraries Menu under Artistic > Artistic_ChalkCharcoalPencil. The Stroke weight is 1 pt except for the short paths inside the letters "O" and "R" for which it is 0.5 pt. Now having all these stroked paths selected go to the Object menu and choose Expand Appearance.

Note: As you can see in the Brushes Panel there are many other brushes available that you can use to obtain a grunge look for your text.
Step 4
After expanding each of the paths stroked earlier turns into a group of shapes. If go to the Layers Panel and open one of these groups you will notice that there is a path which is actually one of the colored paths used at the previous step. It has no stroke and normally shouldn’t affect what follows but I’m telling you that it will therefore you have to delete it. You have to do this for all groups and for each letter until all former colored segments are removed.
Now select all the brush groups and the first letter and click Add to shape area > Expand from the Pathfinder Panel to obtain the new grungy letter "V". Continue with the rest of the letters.

Step 5
Take the Pen Tool (P) and draw a path like below then Stroke it with an Art brush called Chalk that you can find in the Brush Libraries Menu under Artistic > Artistic_ChalkCharcoalPencil. Increase the Stroke weight to 1.5 pt then from the Object menu choose Expand Appearance and Ungroup. Now select only the tiny pieces from the bottom because you don’t need pieces that are too large and too crowded. Group them all then drag the group into the Brushes Panel to define a new Art brush.

Step 6
Next, randomly draw a path over each letter with the Pen Tool (P) then Stroke them using the new Art brush defined earlier. Since the Colorization method was set to Tints you can change the stroke color as you want. If you pick a color you will see how the entire brush stroke looks like but if you choose white you will actually see how the grungy letters will look like at the end. At this point you can move around the paths for further adjustments and when you like how your letters look like go to the Object menu and choose Expand Appearance. Now select one of the letters and the grunge texture above it and click Subtract from shape area > Expand from the Pathfinder Panel. Do the same thing for the rest of the letters and you are done with the first font.

Note: You can use the brush Chalk at this step instead of the new art brush but the grunge texture will be more crowded and will cover a larger part of the letters. I have tried and I didn’t liked the end result and so this is why I have selected only a portion of the brush. If you want to obtain a more pronounced grunge look for your text you can skip the previous step.
Step 7
Here is what we will obtain in the second part using a different type of font:

Step 8
Take the Type Tool (T) and type "Vector" this time using a font called Cataclysmic that you can find here. Select Expand and Ungroup from the Object menu. Now Copy and Paste in front all the letters, remove the fill color and only give them a stroke then go to Object menu > Compound Path > Release.

Step 9
As you did for the other font you must cut these blue paths into segments using the Scissors Tool (C). When you are done Copy and Paste in back all these segments because you will need them later again. You can hide them for the moment.

Step 10
Select all the colored segments and Stroke them with an Art brush called Dry Brush 6 that you can find in the Brush Libraries menu under Artistic > Artistic_Paintbrush. Reduce the Stroke weight to 0.4 pt then having all these paths selected go to the Object menu and choose Expand Appearance.

Step 11
As you did at the step 4 you have to delete all the paths that you used at the previous step that are there in each of the brush groups after expanding. Open each group and delete these paths for all the letters before you continue. Next, select the first letter and all the brush groups on top of it and click Add to shape area > Expand from the Pathfinder Panel to obtain the new grunge letter "V". Do the same thing for the other letters.

Step 12
Now you need the copies of the segments that I said to keep at step 9. Select all the paths above the letter "V" and group them. Stroke the entire group with a Scatter brush called Ink Splash that you can find in the Brush Libraries Menu under Artistic > Artistic_Ink. Reduce the Stroke weight to 0.15 pt. To add more splashes around the letter, Copy and Paste in front the group of paths, keep the same brush stroke and just increase the weight to 0.2 pt. Double click on Stroke in the Appearance Panel to open the Stroke Options window. Here reverse the Rotation values or change them because this way the second group of splashes won’t overlap with the first one. Repeat this step for the other letters.

Step 13
When you are done with all the letters select every group of paths that you have stroked and from the Object menu choose Expand Appearance. Again you have to delete all the paths that you used from each of the groups of splashes, not just the one shown. This is not fun but it needs to be done. When you are finished select the letter "V" and all the groups of splashes above it and click Add to shape area > Expand from the Pathfinder Panel. Repeat the step for the rest of the letters and you are done.

Final Image
This is the final image where I put what I obtained into use. Let me know if you find this method useful.
