The name Borstel refers to towns in Germany. Overall, there are in total 17 different towns and small villages bearing the same name, mainly located in Niedersachsen (a northern state in Germany, 'Lower Saxony' in english).
There is no plausible explanation for this phenomenon. One could just guess that the name Borstel must have been quite popular in medieval ages so that every other village has been named that way (not as popular, in fact, that it has become a personal name; it is just a name for places, not for people). Fortunately, in modern times postal codes have been invented, so that all the Borstels could easily be distinguished.
If you meet someone out of northern Germany's provinces, it is quite likely that this person either a) lives in Borstel, b) had lived in Borstel some time ago, c) knows somebody from Borstel or d) knows how to get to Borstel. Feel free to ask which Borstel.