I used hairspray at my moms house a couple of weeks ago t seat a snowblower tire. The valve stem should be easy. I replaced leaking valve stems on my boat trailer without taking the tire off. Yank out the old ones with pliers, soap up the new ones, push them in and then pull back out to seat it.
Slime sure does make a mess. I have seen it rust some wheels. For what slime costs in a lot of cases you could buy a tube or a tire. When you tube a tire don't forget to pull the thorn or nail out. You would not believe how many people have told me they had a flat and then put a tube in it and it went flat still.
I've used right guard spray deodorant in a pinch before. Worked quite well on the derimmed mini van tire way out in the woods. (Long story involving alcohol). The gang was quite impressed.
If any small tires need replaced or fixed around my place I look for the airless run flats first then fix a flat ideas. Nothing like having limited time and messing with a flat tire in the mud when it's 35 degrees out.
Got another flat on my 4 wheel buggy/wagon ,I think it's the Chinese tubes ,replaced 2 last year , split rims ,PITA Gonna try some slime, Brown Santa dropped it off today