Kill weeds
 

My garden is loaded with Senecio vulgaris (common groundsel) and
Euphorbia peplus (petty spurge).

When hand-weeding, what's the best way to make sure I pull ALL of the
weeds ("ROOTS AND ALL").

After weeding, what can I apply to prevent these weeds from re-
emerging? (Preen Weed Preventer doesn't).