Unless they can prove to you that they meet the halachic definition of an Ani, and/or are “neeman” to collect for real Anyim, there is no reason to give them “tzedaka”. However, there is no need to be mean about it, and there is an exception to feeding an Ani, which should be done without checking (YD 251-10).
Halachicly, if you want to give to Aniyim, you are better off giving to a third party, preferably one which will help get Yiddin jobs. Better then that is to marry off Yesomos, or to pay tuition for limud torah, or support a shul (YD 249 15 & 16, also see Be’er Haytev).
There are halachos regarding how to give Tzedaka (starting in Yoreh Dayah Siman Resh Mem Zayin). You should also ask your Rav what you should do.
For example, your chiyuv to pay your children’s & grandchildren’s tuition comes before other tzedaka (YD 251-3).
End story, ask your Rav.