Can someone send a tallis kattan to a non jewish cleaners to be washed or cleaned?
There is no problem in sending a tallis katan to a non-Jewish cleaners.
However, a Jewish cleaner might be more experienced in dealing with the tallis katan.
In general, one should prefer Jewish establishments, where no substantial loss is involved, as ruled by the Rema (in teshuvos, no. 10), and by the Chafetz Chaim (Ahavas Chessed).