<p>Can any one help me out that how to start a cycle by just using a push button.</p>

<p>Note: Using Marlin firmware, Arduino Mega, Ramps 1.4</p>

<p>I haven't tried altering the Marlin code (as I am new to coding), I was just thinking of adopting this feature as it will be very easy for CNC DIY maker using Marlin code to run a cycle in a loop.</p>

Wood stains (as opposed to dyes, paints, etc.) work by having large particles that become lodged in the grain of the wood, yielding a result that varies in intensity with the grain of the wood and thereby brings out its beauty. It's unlikely that they will do what you want, or anything reasonable, on PLA that has wood particles mixed into it. You might be able to find some types of dyes that will work. I've used wood dyes on woods that don't take stain well and have had good results, and if the PLA+wood material consists of a significant amount of wood, it seems plausible that wood dyes might work well on it.