removing aluminium in grinding wheels

Hey all, brought a second hand bench grinder - and it looks like the prevoius owner has been grinding aluminium on the fine wheel, can l dress these wheels without fear of the f*&%$r's (wheels) exploding, one wheel is pretty thick with Alu like 25%.

l did think of turfing them but thought l'd ask first, the grinder did come with a "dresser"


Stevo