The Salafis say that to make dua with the waseelah/tawassul of Rasulullah (sallallahu alayhi wasallam) or any buzrug who has died is shirk.

Answer

The misguided Salafis do not believe in the concept of Tawassul. They brand it as 'shirk' while Tawassul in which the limits of the Shariah are observed is permissible and meritorious. We have a detailed explanation of Tawassul. Anyone interested, may write for it.