This sounds as simple as it is guys. No matter how much you plan to modify your kit, may it be gunpla, gundam, scale model kits, resin kits and miniatures, you obviously have to clean up the parts thoroughly before doing any sort of modifications.
Clean up does not mean washing the parts ( although you have to do that too ). Clean up means you have to sand off all the nub marks and seal the seam lines ( optional depending on your modifications ).
Why do you have to clean up the nub marks before modding? Simple! Cleaning up while modifying the kit at the same time will super slow you down! If you have a nice sanded kit that is ready for priming, you will be able to focus on just modifications ( panel line scribing, pla plates, etc. ).
Imagine you are about to glue a piece of pla plate or a kotobukiya option part, when all of a sudden there is a nub or excess plastic in the way!!! Dang you all of a sudden have to clean up before gluing the intended part. That is so much hassle if you know what I mean.
Do trust me, you will enjoy the modding stage of your build if you have finished the clean up phase already.
Hope this very simple tip will help you speed up your work! Until next Plastic TIP guys! Just enjoy the hobby! :)