the above answer is not entirely correct, as although the shulchan aruch does not hold of a tavshil shel basar - both by bb"c and nine days, - as opposed to the rema - many later sefardic authorities including ben ish chai, chida, zivchei tzedek and kaf hachaim are makpid for it. therefore as soon as one swallows even that he would need to wait 6 hours- as we are machmir for both rashi and rambams opinions. - shu"a yd 89, 1
see related article here: - in the postscript
regarding placing in mouth and spitting out - it is the shitta of the maharshak that one only requires a rinse - i havent come across any one arguing
regarding chewing and spitting out - although shulchan aruch and others inc. pmg are stringent to wait full 6 hors, r akina eiger, yad yehuda and aruch hashulchan are medayek from rema that 1 hour is enough.
see related great article here:- end of article.
i learn so much from this rabbi spitz's halacha column and i find that many of these questions here are answered by his wise words.