residue in the bottom of left over tren homebrew

hey guys new to the board but i like what i see. ive been in the game for 2.5 years and i love what were all about. i am an avid supported of health , safety, and being a monster. i hope to be a valued addition to your clique. i have some decent knowledge and love to help out. so hopefully you guys will help me out if and when needed. so here goes, i did a wonderful job converting my fina into tren with a finafarm kit. high quality , but any ways that was last summer and i let the remaining product sit around in a cool dark place all winter and spring. now that i want to use it again it has a residue ( red) in the bottum of the bottle (big bottle, it was a 10 gram conversion kit) and i dont kwnow what it is . is it little bits of the stopper from using such a large gauge needle or is it skin or what ? will refiltering with the whatman do it or should it be baked, sterilized and then filtered? or is it ok to use regaurdless?