InteractableParticleSystemObject.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class InteractableParticleSystemObject : VRTK.VRTK_InteractableObject {
    public ParticleSystem ps;
    public int triggerBurst = 50;

    void Start() {
        if (ps == null) {
            ps = GetComponent<ParticleSystem> ();
            if (ps == null) {
                ps = GetComponentInChildren<ParticleSystem> ();
            }
        }
        ps.Stop ();
        this.isGrabbable = true;
        this.isUsable = true;
    }

    public override void StartUsing(VRTK.VRTK_InteractUse usingObject) {
        base.StartUsing(usingObject);
        ps.Play ();
        ps.Emit (triggerBurst);
    }

    public override void StopUsing(VRTK.VRTK_InteractUse usingObject) {
        base.StopUsing(usingObject);
        ps.Stop ();
    }

    public virtual void Grabbed(VRTK.VRTK_InteractGrab currentGrabbingObject = null) {
        base.Grabbed (currentGrabbingObject);
        VRTK.VRTK_InteractUse iu = currentGrabbingObject.gameObject.GetComponent<VRTK.VRTK_InteractUse> ();
        if (iu == null) {
            iu = currentGrabbingObject.gameObject.AddComponent<VRTK.VRTK_InteractUse> ();
        }
    }
}