I'd advise against a ditry bulk for both health reasons, and goal-related reasons.
I assume by bulking you want to gain muscle? A healthy bulking diet will always result in muscle gain with minimal fat gain if done correctly, however with a dirty bulk your far more likely to gain alot of excess fat with your muscle.
In relation to diet- A 'dirty' diet is going to probably be a very acidic and harmful to your overall health. Eating junk food and high glycemic index/refined/unbalanced meals will lead to a higher concentration of Low density Lipids in your blood (bad cholesterol). Increases in fat can cause high blood pressure, and any damage to your vessel walls could easily result in LDL's sticking and providing a base for future athersclerosis as more LDL's, platelets, blood cells, fibrin etc adher over time.
In addition, dirty bulking wreaks havoc with your hormones- especially insulin. Diabetes can result.
On the other hand, a diet full of healthy fats and cholesterol (high denisty lipids) have the opposite effects- HDL's remove cholesterol desposits which may be forming in your arteries.
More vitamins, minerals and a lower acidity content mean better digestive health, better immune health, and better body response. Fat is quickly metabolised, your endocrine/exocrine organs and digestive organs work functionally much quicker, and you have more energy, vitality and better health in general.
So, to conclude- dirty bulking may take less effort/cost less but is significantly offset by the advantages that come with a clean bulk.