maybe there's another way but this might work for you
B4X:
Dim t As String="ÂPÊrÎiÔn"& CRLF &"ÛtŶ"& TAB &"aĈbĜlĤeĴ ŜoŴnẐlẐy"
Dim po As String
Dim c As Int
For x=0 To t.Length-1
c=Asc(t.CharAt(x))
If c>0x20 And c<0x80 Then po=po & Chr(c)
Next
Log(po)
Waiting for debugger to connect...
Program started.
Printableonly
1. You should edit the thread and change the title to a relevant title.
2. If you are working with a limited range of characters then it is possible to implement a simple check like @sorex did (though it is better to use StringBuilder). Catching all the possible non-printable characters will be more difficult.