Re: Tzovei'a on Shabbat
As per Kitzur SA 80:42 it is assur to wipe away even blood with a "mappah" [lest one color it or dye it red.] Lich'ora we may have a built in loophole for a heter in the case of TISSUE paper - since
A it's a davar shelo mitkavein
B it's going to waste anyway - unlike a Mappah
NB: there still may be concerns of p'siq reisheih mitigating this.
Bottom Line -
See Shabtai Frankel edition p. 231 fn 70 giving the related P'saq of the Mishnah Brurah:
"Uvimqom hadchaq - yeish l'haqeil"
I would say "Kol Shekein Yeish l'haqeil" with a Tissue paper that goes to waste anyway
Kein Nireh lee - so far anyway :-)