I always thought that crust was like grindcore, except that the people who play crust are from the gutter and never wash themselves...
Well....just like any other genre people have there own opinion of what bands belong in the genre. But, in my opinion, to start out a few older crust bands like Flux of Pink Indians, Epileptics, Crass, The System, Ruidimentary Peni. Newer ones like Aus Rotten, Behind Enemy Lines, Contravene, AntiProduct, Born/Dead, Nausea, Brother Inferior, Caustic Christ, and etc. The newer Vs. the older crust, sound completely different but I consider them both Crust. There's also an era between those two with bands like Crucifix, Antisect, and Amebix etc.